[WIP] Broccolify

Still need to work on bringing the Travis builds back so that we are testing all of the scenarios (as we are currently).

Opening a PR now to get initial feedback, and to make testing the Travis builds easier.

Builds still needed:

 - [ ] MULTI_BRANCH_TESTS=false TEST_SUITE=packages
 - [ ] MULTI_BRANCH_TESTS=false TEST_SUITE=old_jquery
 - [ ] MULTI_BRANCH_TESTS=false TEST_SUITE=extend_prototypes
 - [ ] MULTI_BRANCH_TESTS=false TEST_SUITE=built
 - [ ] MULTI_BRANCH_TESTS=false TEST_SUITE=standard FORCE_BRANCH=beta
 - [ ] MULTI_BRANCH_TESTS=false TEST_SUITE=standard FORCE_BRANCH=stable