Bug 898296 - Search for Android SDK build tools version 18.0.0. r=gps

This patch also tries to verify that the tools are actually found
early in the configure process, rather than failing with difficult to
parse errors at the end of the build.

Since the Android developer tools are defined earlier in the build
process, we can remove a work-around needed for |make install|.
Bug 899430. Correct incorrect use GetDefaultScale in TextInputHandler to BackingScaleFactor. r=jfkthame

We are converting between cocoa points and dev pixels, cocoa points do not know about our prefs but GetDefaultScale takes into account our prefs, which is wrong.
Bug 892994. On retina screens cocoa rounds widget coordinates to even pixel values, so account for that when placing widgets so we don't get confused. r=mstange
Bug 837242. Part 2. Add a function to calculate the area of an nsRegion. r=roc
Bug 837242. Part 3. Keep track of what area is exposed to events so that covered frames don't get events. r=roc