added uml entry to the Makefile, added Graphviz as a developer requirement.
Added `.depends-dev` dependency. Fixed rebuild and clean.

- only rebuilding on source change
- copying to docs/
- cleaning from docs/
Added .bat extension to pyreverse for Windows.
Merge pull request #19 from jacebrowning/pyreverse

Add UML diagram generation.
Added better README instructions.
Removed link to Python installation.
Removed redundant dependencies.
Changed default to Python 3.4
Switch exe to 'python3' for Travis.
Fixed TCL path.
Merge pull request #20 from jacebrowning/python3.4

Change default version to Python 3.4
Fixed wording.
Removed an extra line.
The default entry point now performs doc/check.
Merge from 'master' branch.