Devices: Make input-mouse more generic

[wpkelso]

Should close #881

Main effort was towards making the specific mouse more generic, rather than emulating the Magic Mouse, as well as pushing towards more parity with the symbolic icon---which does have buttons.

[danirabbit]

I'm not opposed to adding a scroll wheel, but can we at least use a more modern looking design. Something cuter like the Logitech Pebble?

[danirabbit]

Here's a proposal, maybe like this: #1310

• Keeping the overall outer shape, which I like more than just this very rounded rectangle
• Removes the gloss
• Adds a scroll wheel
• Adds a stoke to imply buttons. To do this we have to actually offset everything to the left since you can't draw a stroke exactly in the middle

[wpkelso]

Accidentally nuked this. It's un-nuked on my fork, but it looks like thats not reflected here