Unable to launch zeronet on Linux Ubuntu Arm with

### Step 1: Please describe your environment

* ZeroNet version: ? can not launch Zeronet
* Operating system: Ubuntu 16.04 ARM kernel 4.9.160-armada375
* Web browser: FF

### Step 2: Describe the problem:

I have downloaded Zeronet yesterday from https://github.com/HelloZeroNet/ZeroNet/archive/master.tar.gz
And after trying to u[nsuccessfuly install gevent](https://github.com/pypa/pip/issues/6454), i tried to launch zeronet:

```python zeronet.py
- Starting ZeroNet...
ERROR:root:Unhandled exception: The 'cffi>=1.11.5' distribution was not found and is required by the application
Traceback (most recent call last):
File "zeronet.py", line 18, in main
import main
File "/home/ZeroNet-master/src/main.py", line 13, in
monkey.patch_all(thread=False, subprocess=False)
File "/usr/local/lib/python2.7/dist-packages/gevent/monkey.py", line 966, in patch_all
_notify_patch(events.GeventWillPatchAllEvent(modules_to_patch, kwargs), _warnings)
File "/usr/local/lib/python2.7/dist-packages/gevent/monkey.py", line 168, in _notify_patch
notify_and_call_entry_points(event)
File "/usr/local/lib/python2.7/dist-packages/gevent/events.py", line 112, in notify_and_call_entry_points
subscriber = plugin.load()
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2228, in load
self.require(*args, **kwargs)
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 2245, in require
items = working_set.resolve(reqs, env, installer)
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 829, in resolve
raise DistributionNotFound(req, requirers)
DistributionNotFound: The 'cffi>=1.11.5' distribution was not found and is required by the application
Traceback (most recent call last):
File "zeronet.py", line 88, in
main()
File "zeronet.py", line 53, in main
traceback.print_exc(file=open(config.log_dir + "/error.log", "a"))
AttributeError: 'Config' object has no attribute 'log_dir'
```

Python 2.7.11+
pip 19.1

I have really basic experience about Linux so do not know how to fix python, pip issue. Can you please help me tell which commands to run?