Added keyboard move & span (Super(+Alt)+Arrow-Keys)

[Retnock]

See Comment here: #4 (comment)

First time doing a PR, hope that is how it works :'D

[BasGeertsema]

I have been trying this out, but it seems to interfere with the default behaviour of the Cinnamon Desktop to user <SUPER> + arrow to move windows to the left/right/top/bottom. Sometimes it kinda works and then I can move the window around, but I can´t reliably reproduce this behaviour.

Do you recognize this? How have you been testing this?

[Retnock]

Oh, I see, that one's on me, didnt think about this... I did remap the default Cinnamon + arrow functionality to + WASD on my end a long time ago, so of course there was no interference when I added the move&span for your extension on my end with + arrow.
In the meantime I changed the functionality of my local move&span to + WASD (so I can move and span Windows just with one hand) and completely removed the default Cinnamon Shortcuts (who needs the default if you have something better to move around windows?)
I just did a test and remapped move&span to + arrow, and reenabled the default Cinnamon + Arrow functionality, and can confirm that on my end, the default Cinnamon snapping COMPLETELY overwrites my addon to your extension (same result if I remap both functionalities to + WASD).
Therefore I see 2 possible solutions: Either remap the buttons of the default behaviour, or remap the buttons of my move&span contribution.
For convenience: You can remap the default Cinnamon buttons (at least in Linux Mint) with Preferences -> Keyboard -> Shortcuts -> Window Management -> Tiling and Snaping (or roughly similar names, I translated them, my system language isnt set to english)

PS: Just saw you added support to move windows with the second mouse key, keep up the good work, I'm loving it 👍