Does not work on zsh

``` sh
/s/Executables ❯❯❯ sudo ./ispy 10790 ⏎
Attach process 10790
fatal: Not a git repository (or any parent up to mount point /storage)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
typeset -A git_info
git_info=( )
a: none
asd: none
asd: none
fatal: Not a git repository (or any parent up to mount point /storage)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
typeset -A git_info
git_info=( )
l: alias
l='ls -1A'
ls: alias
ls='ls --group-directories-first --color=auto'
ls: alias
ls='ls --group-directories-first --color=auto'
Brightness hhvm-perms hhvm-perms-reset ispy ReadLog
fatal: Not a git repository (or any parent up to mount point /storage)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
typeset -A git_info
git_info=( )
l: alias
l='ls -1A'
ls: alias
ls='ls --group-directories-first --color=auto'
l: alias
l='ls -1A'
c: none
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: no such file or directory: /var//www
l: alias
l='ls -1A'
ls: alias
fatal: Not a git repository (or any parent up to mount point /storage)
ls='ls --group-directories-first --color=auto'
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
typeset -A git_info
git_info=( )
ls: alias
ls='ls --group-directories-first --color=auto'
Brightness hhvm-perms hhvm-perms-reset ispy ReadLog
fatal: Not a git repository (or any parent up to mount point /storage)
Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set).
typeset -A git_info
git_info=( )
c: none
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
cd: alias
cd='nocorrect cd'
l: alias
Debugger error: [ProcessSignal] Signal signal<133>
Traceback (most recent call last):
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 185, in _main
self.runDebugger()
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 175, in runDebugger
self.syscallTrace(process)
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 126, in syscallTrace
self.syscall(process)
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 130, in syscall
syscall = state.event(self.syscall_options)
File "/home/steel/.pex/install/python_ptrace-0.8.1-py2-none-any.whl.18fa41a1bad5222bc639419593783a12f8c65c79/python_ptrace-0.8.1-py2-none-any.whl/ptrace/debugger/syscall_state.py", line 13, in event
return self.exit()
File "/home/steel/.pex/install/python_ptrace-0.8.1-py2-none-any.whl.18fa41a1bad5222bc639419593783a12f8c65c79/python_ptrace-0.8.1-py2-none-any.whl/ptrace/debugger/syscall_state.py", line 38, in exit
self.process.waitSignals(SIGTRAP)
File "/home/steel/.pex/install/python_ptrace-0.8.1-py2-none-any.whl.18fa41a1bad5222bc639419593783a12f8c65c79/python_ptrace-0.8.1-py2-none-any.whl/ptrace/debugger/process.py", line 726, in waitSignals
return self.debugger.waitSignals(*signals, **{'pid': self.pid})
File "/home/steel/.pex/install/python_ptrace-0.8.1-py2-none-any.whl.18fa41a1bad5222bc639419593783a12f8c65c79/python_ptrace-0.8.1-py2-none-any.whl/ptrace/debugger/debugger.py", line 196, in waitSignals
raise event
ProcessSignal: Signal signal<133>
Terminate
Terminate
Traceback (most recent call last):
File "/storage/Executables/ispy/.bootstrap/_pex/pex.py", line 317, in execute
File "/storage/Executables/ispy/.bootstrap/_pex/pex.py", line 250, in _wrap_coverage
File "/storage/Executables/ispy/.bootstrap/_pex/pex.py", line 282, in _wrap_profiling
File "/storage/Executables/ispy/.bootstrap/_pex/pex.py", line 358, in _execute
File "/storage/Executables/ispy/.bootstrap/_pex/pex.py", line 389, in execute_script
File "/storage/Executables/ispy/.bootstrap/_pex/pex.py", line 403, in execute_content
File "", line 4, in exec_function
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy-0.1.1.dist-info/ispy-0.1.1.data/scripts/ispy", line 5, in
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 210, in main
SyscallTracer().main()
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 178, in main
self._main()
File "/home/steel/.pex/install/ispy-0.1.1-py2-none-any.whl.9e1cb5382cfd6d113d80bf9a99e320d948714a00/ispy-0.1.1-py2-none-any.whl/ispy/ispy.py", line 200, in _main
subprocess.check_output(['kill', '-cont', str(process.pid)])
File "/usr/lib/python2.7/subprocess.py", line 573, in check_output
raise CalledProcessError(retcode, cmd, output=output)
subprocess.CalledProcessError: Command '['kill', '-cont', '10985']' returned non-zero exit status 1
```

Here's the output of the shell it was listening on

``` sh
/s/Executables ❯❯❯ echo $$
10790
/s/Executables ❯❯❯
/s/Executables ❯❯❯ asd
zsh: correct asd to as [nyae]? % /s/Executables ❯❯❯ ls ⏎
Brightness hhvm-perms hhvm-perms-reset ispy ReadLog
/s/Executables ❯❯❯ cd /var//www
cd: no such file or directory: /var//www
/s/Executables ❯❯❯ ls ⏎
Brightness hhvm-perms hhvm-perms-reset ispy ReadLog
/s/Executables ❯❯❯ cd /var
/var ❯❯❯ ls
backups cache crash lib local log mail metrics opt spool tmp lock run
/var ❯❯❯

```

Start in ispy/ispy.py, especially _main, runDebugger, syscallTrace, syscall, and the signal-handling path shown in the traceback. Reproduce the failure by tracing the zsh process with the reported command and compare it with a shell that works. Done means ispy can monitor the zsh session without the ProcessSignal and CalledProcessError failures.

Written by the indexing model from the issue text.