Unify presentation of bit mask and named integer strings.
Merge pull request #116 from square/jw/unify-to-string

Unify presentation of bit mask and named integer strings.
Update Play Services to latest.
Newline.
Add initial API 18 assertions.
Merge pull request #120 from square/jw/api-18

Add initial API 18 assertions.
Add assertions for more util package types.
Merge pull request #121 from square/jw/more-utils

Add assertions for more util package types.
Merge master