Twips-conversion fixes in Transform and MouseEvent

Fixes #681
Silence spammy Closure Compiler warnings
Merge pull request #683 from tschneidereit/master

Twips-conversion fixes in Transform and MouseEvent
Adds support for centered and right-aligned text in dynamic TextFields
Adds a bin-packing algorithm for creating compact sprite sheets.
Fixes positioning of non-left-aligned text in auto-sized text fields
Merge pull request #684 from tschneidereit/master

Fixes for text-alignment and TextField sizing issues
Merge branch 'master' of https://github.com/mozilla/shumway into gl
Cosmetic changes, adds settings tab with dat.ui.
Better texture mapping.