Add party picker for primaries
Do not hide empty views in contest list.

Otherwise there are sometimes spacing issues.
Add test for contest party filter
Add modified tab bar nine-patch files from design team
Clarify party picker description strings
Show loading message while querying for directions
Cache directions query responses.

Stores for session valid responses that match on origin, destination, and mode.
Scale down large images
Get contest from party-filtered list in candidate view
Use LRU cache for candidate photos
Add voter servicees icon to details layout
Style 'About' view
Changes to prevent random Travis build failures.

Tests seem to get killed on Travis sometimes, perhaps due to going over the 3GB memory limit on Travis.
Merge pull request #35 from flibbertigibbet/feature/add-party-picker

Feature/add party picker