[sldev] [VWR] [PATCH] Flycam support for Mac OS X

[Ettore Pasquini]

My first patch, finally. I implemented flycam support on Mac OS X.

Main things worth noting:
- I refactored the current implementation in two ways: (1) abstracting out
OS-specific device initialization into a separate, minimal, reusable
"libndofdev" library; (2) cleaning up the LLWindow hierarchy with joystick
related junk and putting that in the more proper LLViewerJoystick class.
(Why having a joystick class when all the main joystick functions are inside
a window hierarchy?)
- I used Apple's HID Utilities sample code because it's free and it works.
- Linux is to do, but I will do it when I get some free time.

I know it's a fairly big chunk of stuff, but there was no "small" way around
it. Any problems you notice, please let me know. More details here:

http://jira.secondlife.com/browse/VWR-2516


Ettore