Allow locale override

[idpaterson]

The workflow supports only English menu language and task entry keywords (due, remind me, etc), but dates need to be entered in the user's locale. This is never particularly obvious and sometimes it just doesn't work. I'm trying to improve date handling for other locales.

I added a quick "force English" preference in response to this issue but do not plan to release that. Instead, a preference should be added that allows the user to select either their system locale or one of the other built-in parsedatetime locales. This screen can show examples from Calendar.ptc.locale.* like month names, weekday names, and "today" in each language. This should also include reorganization of the preferences as described in #106.

Discussion

1. Should English be the default, requiring an explicit preference change to use a different locale?
   • This might avoid confusion since the main documentation and examples for the workflow will work regardless of locale
2. Would anyone be willing to help me write test cases for date expressions in German, Russian, French, Spanish, Dutch, or Portuguese in parsedatetime over the next few months?

[mihan007]

1. Yes
2. I'm going to help with Russian. If you can point me to preferrable format of test cases that would be great. As of now I may provide "Russian" => "English" datetime pairs and vice versa.