BUG: 375376

This revision adds dark mode support to the app ( T7044 ). It does so by injecting

theme information into each activity, and making sure that all Views

define their colors by reference to theme attributes.

In order to make this work, all of the buttons with images (like the list

of available devices) now are tinted according to the theme.

While all versions of android support the theme, only devices running

Android ICS or higher will have a toggle button in the drawer.