Extract a bunch of maintainable dictionary files.

This is the first patch to restructure the dictionary file into a number of
distinct files that match a relevant theme. Plover should load all of these
files at startup, and use them collectively as the default dictionary.
Add support for combining multiple dictionaries into the default
Merge pull request #169 from balshetzer/master

Add support for combining multiple dictionaries into the default
Merge branch 'master' of https://github.com/Zackrobat/plover into Zackrobat-master

Fixed some conflicts and removed a spurious print.
Merge branch 'master' of https://github.com/openstenoproject/plover