fix tests that relied on translation structures being statically cached.
clean up static cache, add test for German imperative (WIP)
verify that my plan for making the German infinitive an optional alias will work.
allow json config to contain a list of config files (includes).
read json config file if available.
missed an include, broke the build.
read keywords from json configuration, use German imperative forms.
fix broken test that didn't like the new init_locale() requirements.
Merge pull request #46 from badgerman/master

German keywords in the imperative.