pidcat can't find adb

system: Arch Linux 3.9.6-1 x86_64
python version: 2.7.5 and 3.3.2
pidcat version: 571826e8c03b18402025c6d8bd8bad1d367401a8

```
Traceback (most recent call last):
File ".bin/pidcat.py", line 142, in
adb = subprocess.Popen(adb_command, stdin=PIPE, stdout=PIPE, stderr=PIPE)
File "/usr/lib/python2.7/subprocess.py", line 711, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1308, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
```

~/.bashrc

```
export ANDROID_HOME="~/android-sdk-linux"
export PATH="$ANDROID_HOME/platform-tools:$PATH"
```

Start with .bin/pidcat.py around line 142, where subprocess.Popen invokes adb, and compare that command with the PATH setup shown in .bashrc. Reproduce the Errno 2 failure using the reported environment, then verify that pidcat can locate and launch adb successfully.

Written by the indexing model from the issue text.