v1.1

Key null checks, keyboard interaction, key prefab

Added some null checks when dealing with keys;
Added key selection movement and selection on keyboard, with char concat on string buffer;
Added a key prefab to spend less time in key generation and keyboard building.

v1.0

Key null checks, keyboard interaction, key prefab

Added some null checks when dealing with keys;
Added key selection movement and selection on keyboard, with char concat on string buffer;
Added a key prefab to spend less time in key generation and keyboard building.