Better workdir tests, fixed git commit method.

Removed repo.refs.set_symbolic_ref('HEAD', ref) as it
does similar to what branch checkout does without updating
wokring directory files (which should not occur at
in memory commit)
Updated ignore files
Updated readme
Updated parameter name for get_scm at cli. Fixes #109
Small cleanups before release
Updated travis / setup.py
Latest 2.5.X series of Mercurial is 2.5.4
Updated get_gitdiff, log command and added a test. Fixes #110.
Merge branch 'master' of github.com:codeinn/vcs
fixed missing tee import
Use mercurial 2.5.2, not 2.5.4
Merge branch 'master' of github.com:codeinn/vcs
Freezying v0.4
Bumped version
Added requirements.txt for docs build (for readthedocs)