Use GetMouseMovePointsEx to smooth mouse input.

Uses GetMouseMovePointsEx to get mouse move history so mouse events aren't dropped even with low framerates.

Fixes #76.
Use Marshal.GetLastWin32Error instead of GetLastError.

Also removes magic number 1171 and replaces with constant.
Merge remote-tracking branch 'frassle/issue76' into develop
[Examples] Test mouse input under heavy load