Keybord support improved

*Improved Keyboard:
- Fixed crash when using Null keyboard handler
- Added support for meta keys
- Added support for {caps, num, scroll} lock.

*Small issues fixed in previous module:
- cellGifDec: Fixed wrong information of packet field in
cellGifDecReadHeader.
- cellGifDec: Set DataOutInfo.recordType as 1 since the output is always
an image.
- cellJpgDec: Set colorSpace as 3, until a better function is
implemented.
- cellJpgDec, cellPngDec: Added RGBA support.

*Changed layout of "Config > Settings" menu.