merged 28477:29285 from trunk
gpencil simplified filtering, unbiased smoothing, and pen eraser that works
fixed tablet mouse spasm bug and refactored event handling
added working notes, exploratiions and mis-steps
hint for mouse/pen input fidelity
removed unused #include
guarding printf calls as MinGW (gcc 4.5) insists
preparing for NDOF overhaul
much-improved tablet handling; hi-fi input for mouse/pen
human-readable nonsense
added filtered event dispatch for lo-fi mouse/pen input
disabled lo-fi dispatch log to reduce event debugging noise
Improved tablet support on Windows. Nice deep queue for input points. Much more is being captured now. WT_PACKET events are disabled until I can revisit in a day or two.

Also added Wacom's driver wrappers, with their permission. These won't live here very long, but the WindowWin32 tablet code uses it for now.
Hi-fi mouse input on Windows!

The remains of a RawInput mouse attempt are included, but disabled. RawInput will still be used for multi-axis devices. 

Eliminated the need for several #defines by requiring WinXP or newer.
Tweak Windows #includes to require WinXP or newer and speed up build times.
More ramblings from a certain mad scientist.
fixed misspelled variable in Wacom utility
Added rudimentary SpaceNav event capture code for Windows.

Disabled RawInput mouse code.
removed unused Macintosh Carbon code
removed more unused Macintosh Carbon code