Update devDependencies

Notes:

1. I simply disabled latedef for collapse.js. We could refactor the code instead
2. Only issue left is https://github.com/twbs/bootstrap/commit/0820da3f52b83415a694ba181d7bbc5e3dd2cc68#commitcomment-16466850

TODO:

• Change the instructions for bundle if we go with this approach.
• Clean up env globals
• Caching doesn't seem to work with trusty image
• Fix the qunit failure

/CC @cvrebert @patrickhlauke (for the validation fixes)