refactored disable context generating functions into grammar config module
Merge pull request #75 from mzizzi/config-disable-contexts

refactored context generating functions into grammar config module
Add Alias class for managing aliases.
Integrate new Alias class into make_grammar_commands.
Added reference to Google group.
Update readme.
Merge https://github.com/dictation-toolbox/aenea into aliases

Conflicts:
	client/aenea/configuration.py
Don't clutter the aenea package with everything in alias.py
Make Alias a new-style class since we're using Python 2.