MacOS non-centered secondary display.

[BrianPugh]

First off, loving deskhop!

I'm currently using deskhop between 2 macos devices. One of them has 2 displays. When the displays are arranged such that the second monitor is to the left and intersects the center of the primary monitor, everything works. When the secondary monitor does not intersect the center of the primary monitor, I am unable to move the mouse to the secondary display (the mouse cursor wraps around).

Works:

Does NOT work:

I don't think this is too uncommon of a configuration (e.g. macbook open on a desk with the builtin monitor as the secondary display).

[BrianPugh]

for anyone that sees this, all my desired features and bugfixes are in #312 and are in the process of review.