Documentation, formatting, code polishing

Sphinx generated documentation can be found at ReadTheDocs (link in the README).
Code follows PEP8 Style Guide coding conventions.
Example blueprints (XML) can be found in examples folder.

Rectangular mask added

Commands 'select' and 'mask' added.

All essential parts

Code refactoring.
Export colors used in blueprint to Gimp palette.

Basic functionality

v1.1

Code polishing. Better xml information nesting.