Add support for native mouse cursors in pyglet

[learn-more]

To test this, open the demo dialog,
Expand 'Inputs, Navigation & Focus' (last item)
Expand the 'Mouse cursors' (last item)

Hover over the lines describing the cursors.

Only tested on Windows 10.

[coveralls]

Coverage decreased (-0.3%) to 55.613% when pulling f0115f7 on learn-more:add_cursor_hand into 480b4de on swistakm:master.

[learn-more]

@swistakm Would you have some time to take a look at this?

[Qlii256]

I was just trying to change the mouse cursor and can confirm it does not work with the latest PIP build. This integration seems to work fine! I also noticed that the MOUSE_CURSOR_HAND is missing as a constant, was this added in another commit because this "fix" does not include it.

[learn-more]

I was just trying to change the mouse cursor and can confirm it does not work with the latest PIP build. This integration seems to work fine! I also noticed that the MOUSE_CURSOR_HAND is missing as a constant, was this added in another commit because this "fix" does not include it.

This fix is based on the current pyimgui version, which includes an old imgui.
This hand cursor was added in a later imgui version.