Mac version attempts to use git, but ends up working without it

[goba]

On a Mac without developer tools it pops this up as the installation starts. I cancel out of it. Then just it is about to end the installation, it pops it up again. There is not a visible damage to the installation after this (and it does not pop up again other than these 2 times in the initial run). But this makes it hard to recommend for actual non-devs to use, since it will feel like an error to them.

[phenaproxima]

Fixed in #40.