Use git:// url instead of https:// for runtime submodule

It seems Heroku no longer detects/pulls in the sub
NPM: Disable postinstall hook
Debug Heroku build fail
Heroku: Use custom buildpack for git submodule

Doesnt seem like normal Heroku flow picks up my module at al...
Heroku: Use custom git submodule buildpack
Heroku: Attempt to use not-renamed buildpack
Heroku: Add buildpack earlier
Verify that .gitmodules exist
gitmodules: Copy of .gitmodules, to prevent Heroku destroying it
Don't check for .gitmodules
server: Default to local case, use IMGFLO_CACHE=s3 to override
Merge remote-tracking branch 'origin/master'