Input event changes

- New InputEventManager class.  It will be used by 3rd party input
devices to generate Torque 3D input events.
- Expanded the input event signal to include three new floats and a new
integer.
- Expanded the number of joystick buttons to 48.
- The input virtual map is now extendable rather than hard coded.
- The input devices types are now extendable rather than hard coded.
- New SI_POS, SI_ROT, SI_INT, and SI_FLOAT input event types.
- New SI_VALUE input action type.
- ActionMap has been updated to work with these changes.
- Removed unnecessary references to platform/event.h
Merge pull request #219 from DavidWyand-GG/InputEventManager

Input event changes