This ensures your local copy of this folder is up to date whenever
mcdev imports change on the project.
Before, as we/upstream add/remove's imports, your local folder could
be out of sync and you have to randomly check 'do i need to run this?'
This will just automate it. For those people who don't use this
folder (not sure why you don't!), it won't change anything.
ac12a97076