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.
Fix Python extension naming on Windows.

The extensions should not be versioned (-avoid-version), and for native Windows
Python, modules should have a '.pyd' extension.
Add comments, fix an uninitialized variable.
Remove redundant assignment.
Merge pull request #1418 from fontforge/issue_1414

Comments.
Merge pull request #1421 from tshinnic/master

Fix allocation size calculation in svg.c
Merge pull request #1417 from jtanx/py-ext

Fix Python extension naming on Windows.
Merge pull request #1409 from jtanx/gdraw

Some GDraw Fixes
Address issue #1427 by removing PListCreate in ufo.c.
Merge pull request #1428 from fontforge/ufo_libxml2_1

Remove PListCreate in ufo.c.
Added Python accessors for getting and setting point names.
Added documentation for the new "name" field of the point class.
Work through the compiler warnings and take action as necessary.

This fixes most of the warnings, except for:
* Any collab code
* fontforge/ufo.c (skipped)
* encoding.c: Assigning const parameter AdobeStdEncoding to what may be free'd
  - No easy way to resolve this
* charview.c: 12910 - Should this be cast or converted?
  > mblist_nomm[i].ti.text_untranslated = mblist_nomm[i].ti.text;
* cvpalettes.c: Redefinitions of MID_*
* metricsview.c: selectUserChosenWordListGlyphs - Comparing GArray pointer against 0 / -1 / -2 ?
* windowmenu.c: Same question as for charview.c
  > e.g:
  > windowmenu.c:270:33: warning: assignment makes pointer from integer without a cast
      mb[i].ti.text_untranslated = mb[i].shortcut;
Work through the compiler warnings in ufo.c

These functions could not be declared with const SplineChar* because one
or more functions that they subsequently call modify that parameter:
* UFOOutputFontInfo
* UFOOutputFeatures
* WriteUFOFont

The most notable example is a call which leads to SFReadChar being called.
There may be other functions which also modify the parameter, but tracing
the calls is tedious.
Test for headers and library for FONTFORGE_ARG_WITH_LIBPNG()

Replaced pkg-config check with a check for headers and library.
./configure does a hard-stop if user specifies '--with-png' and there is
no library or developer files available. Fixed *.pc dependency list.
Fix const usage warnings when compiling on Linux
Missed adding to test != xno
Merge pull request #1431 from tshinnic/master

This seems to remove automatic path closure but to fix a bug that stopped commanded path closure in certain cases due to bad parsing.