Refactoring browser_compat.js.

postile.browser_compat.* are moved to postile.conf.useragent.*, while
interfaces stay the same. Boilerplate code are replaced with goog.userAgent.*
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'origin/master'
Refactoring postile.fx.Animate

Changed fx.Animate()'s signature to accept an optional argument object
instead of three optional arguments.

Renamed fx.mode into fx.Mode.

Added some comments.
Merge remote-tracking branch 'origin/master'

Conflicts:
	js/postile/view/post_board/post_board.js
	js/postile/view/post_board/post_in_board.js

Merging fx.Animate changes into master. Please see one of the parent
commit by Overmind for more details.