Updated French translation in Windows installer.
Little cleanups in code.

Show WebGL enabled with QtWebKit 2.3 only on Linux.
Added QtWebKit platform plugin for notifications and spellcheck.

It's mostly just copied implementation from qtwebkit-plugins repo.
Spellcheck is only very basic.

Spellcheck will be automaticaly compiled if pkg-config detects
installed hunspell library.
Merge branch 'master' into source_in_tab

Conflicts:
	src/lib/lib.pro
fix GET parameters