Win32: Discard mouse move event if pos hasn't changed. Fixes #1390

Full credit for this fix goes to 'unofficial-fontforge-cygwin'
for this patch: See http://www.geocities.jp/meir000/fontforge/ -
in particular http://www.geocities.jp/meir000/fontforge/fontforge-20140104-cygwin.patch.txt.

For some reason, mouse move events are fired, even if the mouse
hasn't moved. This caused tooltips to disappear immediately as
they were shown.
Handle scroll wheel usage properly in the menus.
Fix resource loading on Windows and standardize path normalization

* backslash to slash calls/procedures have been/should be replaced
  with GFileNormalizePath/u_GFileNormalizePath. I think I have
  replaced all instances.
* Resources requires the executable extension to be stripped on
  Windows, otherwise 'fontforge.*' resources are ignored.
  Symptoms include: The background not being white, colours not
  being obeyed etc.
Merge pull request #1409 from jtanx/gdraw

Some GDraw Fixes