[KT] Code style fixes.
[KBSwitch] Link to xkbfile.
[KBSwitch] Load & store rules/layouts.
[KBSwitch] Fixed a typo.
[KBSwitch] KBCtl::GetCurrentGroup().
[KBSwitch] Added QuarkProxy.
[KBSwitch] Added layout quark.
[KBSwitch] Added FlagIconProvider.
[KBSwitch] Show keyboard layout flag.
[KBSwitch] KBCtl::Get{EnabledGroups,LayoutsD2N}().
[KBSwitch] Fixed FlagIconProvider license.
[KBSwitch] Added LayoutsConfigWidget stubs.
[KBSwitch] Show LayoutsConfigWidget in settings.
[Util] Added ModelIterator.
[KBSwitch] Style fixes.
[KBSwitch] KBCtl::GetMaxEnabledGroups().
[KBSwitch] Enable/disable layout actions.
[KBSwitch] Setup rules before all.
[KBSwitch] Store groups as codes, not as descs.
[KBSwitch] Basic modification methods.