Bug 983208 - Fix progressive tile update calculations. r=botond, a=lsblakk

A lot of this code used incorrect coordinate spaces or calculations that only
worked because things were setup in a certain way. Now that the input data is
more consistently correct and things have changed slightly, this code no
longer worked.

This patch reworks things to use what I think are the correct coordinate
spaces and calculations, and should hopefully be less prone to breakage.
Bug 985554 - Add es-MX to mobile/android/locales/all-locales. r=Pike, a=lsblakk