Bug 916315 - Enable CSS sticky positioning in release desktop builds. r=dbaron

- CSS Sticky positioning has already been enabled for B2G.
- This patch enables the layout.css.sticky.enabled preference by default for
  desktop builds.
Bug 957513 - DecimalIntegerLiteral cannot be 0 directly followed by 8 or 9. r=jorendorff, r=vp
Bug 957721 - Switch mach's shebang to look for python2.7. r=glandium

OpenBSD doesn't have "python" on $PATH by default. "python" may also
come from a non-2.7 Python. Switching the shebang will help ensure the
user invokes mach with Python 2.7.
Bug 1004579 - Change pref so drawFocusIfNeeded is enabled by default. r=surkov
Bug 1005657 - For the Unicode table, check that all the glyphs are found and come from the same font. r=karlt