Add NPM/Bower dependencies check

[digitpaint]

Add NPM/Bower dependencies check

[flurin]

Bower has the option to output json so that should be consumable bower list --json says "missing" if a dependency is missing.

NPM I'm not sure but it should have an option like that as well.

Question is: should this be a plugin? IMHO: yes.

[edwinvdgraaf]

I'm not sure about yet another plugin, finding the setup time for each plugin to by quite
costly already. However, it's really specific functionality which doesn't necessarily belongs
inside roger.

[edwinvdgraaf]

Closing this one.

Bower seems fading, npm is still a strange, but solution should be found outside roger. Think shrinkwrap, build from clean environments etc.