The GOPATH is not correctly set up in the virtual machine

[Zteve]

Currently, the GOPATH is set to be ~/go from the host (by linking and shadowing the host folder). This assumes the host ~/go exists and is the right path.

Experimental code managed to successfully set GOPATH to the first item in the host's GOPATH, but this isn't right either.

Solution could be to reflect the entire GOPATH of the host machine (programmatically in the (Ruby) Vagrantfile); but this is fragile and possibly over-complicated.

Finally, we could just make this something for the user to do with hooks in the setup.sh script.

[Zteve]

Forgot to add that doc needs updating.