Move to Android Studio/Gradle

Also ditch SlidingMenu for built in DrawerLayout.
Separate fragments and activites.
Add post activity, update icons, etc.
Add refresh button to thread detail view.
Add and use simple view injector.
Parse body of comment once when loaded.

This fixes spoilers from becoming unspoiled because the state is saved
in the SpoilerSpan, and this no longer re-parses the comment and creates
a new SpoilerSpan each time.

Yes, I edited a file that says "do not edit" at the top.
Add internal browser fragment.
Fix browser clobbering thread view.
Fix back button when in browser.
Save thread list state.
Make browser progrss bar a little better.
Change internal browser to an Activity.
Add Crashlytics.
Fix possible error refreshing thread.
Reset page number before loading data.
Fix crash is browser when zoom buttons are shown.
Update preference names.
Set background color based on user setting.
Inherit background color from the activity.
Display number of new posts per thread.