Fix missing return values
Add a generic cross platform replacement for xhotkeymanager
See details:

 * Handle mods correctly (ProposalList)
 * Move eventhandling to into their related classes
 * -> (ProposalList,  InputLine)
 * Replace XHotkeyManager by GlobalHotkey
 * Set correct forcus policies and proxies
 * Fix ugly "XFocusEvent while grabbed" Bug (Still a workaround)
 * Make mainwidget a singleton
 * Hide if inputline loses focus
 * Make actions accessible over model-view
Add proper shortcuts
Unregister old hotkeys before adding new ones