lwjgl Joystick support

[Matzon]

There - Joystick added for the Windows platform. Could anybody with a joystick please pull the source code from cvs and test it?

The test class is: org.lwjgl.input.test.JoystickTest.

Currently (and for some time, unless someone convinces me otherwise!) the implementation will only support the first attached Joystick.
The joystick class supports:
- x axis
- y axis
- z axis (throttle)
- pov (Point of View (or HAT))
- n buttons (where n is determined natively (in DX, 128 buttons) - the buttoncount might be locked to say 8 buttons in a near future, to make certain that we don't choose a value that is to high for some platforms.)

Please note that this is the first attempt, so things might not work as expected...