Fix unbalanced super class call.
Properly use constants.
Replace restartLoader() by Loader.onContentChanged().

Just restarting the loader won't force a data refresh.
Switch to SherlockProgressFragment.

Fixes calling invalidateOptionsMenu() on API 10.
Suppress errors for using
SherlockFragmentActivity.invalidateOptionsMenu().
Store theme setting in a format controlled by us.

R.style.* can change over time (dependant on build settings, used
libraries etc.), so we should rather not use it as a theme setting
lookup key and blindly trust it on reading from persistent storage.
Fix unused imports.
Allow opening, closing and merging pull requests.
Add refresh menu items for issue and pull request.