GB now supported for Go builds

Change effective on 04 February 2016

Heroku can now build go projects that use GB to manage dependencies.

To get more information about using GB for Go applications you can look at our overview in this devcenter article or the GB website.

In addition older, already deprecated legacy .godir and Godeps file (only used by really old versions of godep, not to be confused with Godeps/Godeps.json) support has been removed.