chore(deps): use HTTPS for fetching npm modules

This stops npm from erroring with useful messages like this:

    npm ERR! git clone git://github.com/karma-runner/karma-coverage Cloning into bare repository '/home/fidian/.npm/_git-remotes/git-github-com-karma-runner-karma-coverage-f5a5ab06'...
    npm ERR! git clone git://github.com/karma-runner/karma-coverage
    npm ERR! git clone git://github.com/karma-runner/karma-coverage fatal: unable to connect to github.com:
    npm ERR! git clone git://github.com/karma-runner/karma-coverage github.com[0: 192.30.252.129]: errno=Connection refused

and like this

	npm ERR! not a package /home/fidian/tmp/npm-17172/1382734998255-0.33902470069006085/tmp.tgz
	npm ERR! Error: ENOENT, open '/home/fidian/tmp/npm-17172/1382734998255-0.33902470069006085/package/package.json'