using CDN, hoping to fix#773 (hoping! will follow up). We can close#755 as a result. We use
require() to min/concat for performance. Note, previously we had "too
many files open" error because we had /vendor tracking git submodules,
which includes all files for those projects - now we're downloading
manually, which gives us minimum required files from each project's
build steps
reason we're removing the submodules (intead of keeping them around
for offline development) is that derby does some watchfile magic on the
public directory, and it causes a "max file limit" operating system
error (mitigated by `ulimit -u 2048`). For offline developers, you may
want to have some symlinks and a git stash handy
