tools: update eslint to v2.2.0

[dnalborczyk]

update eslint from v2.1.0 to v2.2.0 for new features and bug fixes

blog:
http://eslint.org/blog/2016/02/eslint-v2.2.0-released

changelog:
https://github.com/eslint/eslint/blob/master/CHANGELOG.md

[rvagg]

perhaps we can wait for the next release? not so great that the test suite is broken eslint/eslint#5415

[silverwind]

Yes, I think we're better off waiting. There's not much to get excited about in 2.2.0.

[silverwind]

@dnalborczyk thanks for the contribution, but I don't think we can take it for above reasons. If 2.3.0 proves to be of value to us, we can check that out.

Note that we take a few extra steps when updating ESLint, outlined here (We should document these better).

[dnalborczyk]

No problem. Though I wasn't aware of this, I did follow pretty much the same procedure:

delete tools/eslint
npm install eslint --production (which leaves out dev dependencies)
copy eslint from node_modules to tools, copy (remaining) node_modules folder.

Daniel

[silverwind]

Yeah, I was mostly pointing out dnm to remove more unneccessary files :)

[dnalborczyk]

Ah, I see, I missed that. Thanks for pointing that out, much appreciated! I didn't know such a tool existed. :)