Add ability to toggle window visibility (to/from Tray) [$30]

Hi everybody,

That's great we the users of KeePassX have a new dev team for the app!

It would be nice to have an Option called Toggle Window Visibility binded to a global key combination (like the auto-complete) to bring the main window to front and to minimize it with the same key combination. If the minimize-to-tray option is enabled, the minimize action of this option should minimize the window to tray.

To give this issues a higher priority, I'm willing to contribute economically. Those who could implement it please specify how much should be collected and I could contribute to the implementation on bountysource.com or your crowdfunding site of preference.