[ios] - implement the UIInputKey protocol - enables bt keyboard support for ios devices (all printable chars, no modifiers, no cursors)
[ios] - hack into the gsevent object of events for catching the cursor key events of bt keyboards. This makes bt keyboards useable on ios (without cursor keys its a bit stupid).
Merge pull request #3282 from Memphiz/iosbtkeys

[ios] - add support for bluetooth keyboard