Replace viewpager, switch to appcompat actionbar, clean up code.

Reverted viewpager to official version, modified viewpager code was causing fragment leaks in rare cases.

Switched to official appcompat actionbar library, it doesn't change much from our perspective.

Also removed some dead or useless code, including the fragmentMessenger stuff which we never really used.

Features removed:
-Scroll-lock option, which was built upon the hacks introduced into the modified viewpager.
-Tablet Split-UI - It was a poor workaround and better options can be pursued.
-Code/Pre block scrolling - barely worked anyways, webview would constantly fight the viewpager for touch events even with the workaround. Suggest line-breaking pre blocks like the iOS app does.

Follow-ups needed will be an updated tablet UI, possibly eliminating the viewpager altogether. Looking into SlidingMenu.