v0.0.2: Complete python implementation

This oversized commit completes the implementation of pat in python by
removing the shell script and placing all program logic into pat.py,
complete with a new configuration file.

Closes issue #3:

       3 - Complete implementation in Python

       There's no need to mix shell/python.

       https://github.com/ChrisCummins/pat/issues/3

Closes issue #2:

      2 - Write patrc in python

      https://github.com/ChrisCummins/pat/issues/2

Closes issue #5:

       5 - Expand ~ in paths

       https://github.com/ChrisCummins/pat/issues/5
Merge branch 'wip/iss3'