Minor fix to allow for multiple ticks to be received at one time by the

Minor fix to allow for multiple ticks to be received at one time by the
WIN32 code.  Take abs(direction) as the number of ticks, and count it
down.

<stdlib.h> *should* be included by freeglut_internal.h, I think, so it
should be okay; otherwise add a suitable #include.

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@268 7f0cb862-5218-0410-a997-914c9d46530a