Change from John (I removed a couple of spaces from a couple of lines in

his freeglut_internal.h file where they were wrapping in EMACS; otherwise,
the files are exactly as he sent them to me).

The change unifies the WIN32 and UNIX_X11 code by defining our own
window-handle-type in freeglut_internal.h.  This let John rip out some
#if garbage in several places.  The result is clearer code.

Thanks, John!

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@362 7f0cb862-5218-0410-a997-914c9d46530a