Adjust default font sizes
Cleanup displayed build configuration flags in qupzilla:config

Removed KDE Integration and WebGL. Both flags don't have much use now.
KDE Integration only enables KWallet plugin building (and only when
KWallet-dev is available).
WebGL is now enabled by default by any recent QtWebKit versions.

Also show Win7API flag only on Windows.
Settings: Allow nesting instances without breaking groups

Closes #1511
Mac: Fix Preferences... action in application menu

Make sure the Configuration Information action won't be
detected as "Preferences..." action.

Also use native shortcut for fullscreen (Ctrl+Meta+F)

Closes #1332
Fix build with Qt 4.7
Version 1.8.4