Consolidate field names

The models for Category, FundingCategory, MusicFocus, Topic and Type have different names for the name of object.

We should consolidate the field names and rename the fields before the 1.0 release:

• Category.category -> Category.name
• FundingCategory.fundingcategory -> FundingCategory.name
• MusicFocus.focus -> MusicFocus.name
• Topic.topic -> Topic.name
• Type.type -> Type.name

There are fields in the RRule, Show and Schedule models that should be renamed:

• RRule.bysetpos -> RRule.by_set_pos
• Show.fundingcategory -> Show.funding_category
• Show.musicfocus -> Show.music_focus
• Schedule.byweekday -> Schedule.by_weekday
• Schedule.dstart -> Schedule.first_date
• Schedule.until -> Schedule.last_date
• Schedule.tstart -> Schedule.start_time
• Schedule.tend -> Schedule.end_time

This would affect the models, the serializers, the REST API, as well as the dashboard.