Fixes hide keyboard bug on done/discard

- Previously, the keyboard would remain open after editing a Stack as per [this bug](https://www.pivotaltracker.com/s/projects/848089/stories/52677857)
- This fixes it by explicitly hiding the keyboard when either done or discard is pressed.
Adds translucent options to remaining Crouton colors.

- adds translucent versions (80% opaque) of the existing Holo colors which are used for Croutons
- refactored color names postfixing "translucent" instead of the opacity