Extend InputText capabilities

[zcanann]

InputText should be updated to support:

• Support highlighting
• Support ctrl+Z
• Support click-to-move cursor positions

This should greatly improve the UX of editing code

User Request* : running a vim emulator within the cocos text buffer.

[zcanann]

Add a character limit to function names too

[mattbucci]

Update: the keycode on mac for cmd+z is "Key_Hyper" for cmd