Mirror https://github.com/rd2/tbd to an NREL repo

[kbenne]

OpenStudio (via openstudio-gems) currently pulls tbd from @jmarrec's fork. I think we should leave it this way for the upcoming 3.8 release, however going forward I think this needs to be resolved, by creating an NREL fork that OpenStudio can build from. I don't think it is wise to have a third party repo on the critical path for the OpenStudio build.

[jmarrec]

Not saying this shouldn't be done anyways as I'm sure we'll run into situations in the future where we need to pull from github rather than rubygems, but as of last night openstudio-gems is back pulling from rubygems for these.