basic part of #17 show a program's permissions in a nicely formatted way

basic part of: https://github.com/subuser-security/subuser/issues/17

 subuser install should show a program's permissions in a nicely formatted way, like in android. #17 

Still needs at later time refactor of subprocess calls to pure python code as suggested


output something like:

```
workerm@notebook:~$ subuser install vim
vim is already installed.


========= PERMISSION.json for: <vim> =========

{
  "description": "A simple powerful text editor", 
  "maintainer": "Timothy Hobbs <timothyhobbs (at) seznam dot cz>", 
  "last-update-time": "2014-02-12-12:59", 
  "executable": "/usr/bin/vim", 
  "x11": false, 
  "inherit-working-directory": true, 
  "allow-network-access": false
}
workerm@notebook:~$ 
```

only for explicit installed programs