GoAT package in the AUR

[tlgs]

Hi! Thank you for working on GoAT, I've found it very useful.

I wanted to make it available for my system so I've recently packaged it for the AUR; this way Arch Linux users can easily install the goat command line utility using their system's package manager.

A couple of notes:

• I've packaged it as a VCS package. This wouldn't be my first choice, but as there are no tags or releases, this is currently the best approach. Please consider tagging some commits as important versions, this would make the package more stable and enable integrity checks (such as verifying signing keys or sha sums).
• The utility is installed as go-ascii-tool. Unfortunately, another package (upstream) made it to the "goat" name before me. Users can always alias. :)