use semistandard

[makepanic]

should fix #2490

[makepanic]

I think there's a problem because config-semistandard and config-standard depend on eslint > 3.
Eslint > 3 requires node 4 or greater.

Nevermind, I think with some version pinning we could get it to work on old node.

[boneskull]

I'm fine with requiring Node.js 4.x for linting (and newest ESLint). We only really need to run tests on multiple versions of Node.js--and even then, just in CI. We need to lint once.

Best way to accomplish that? Not sure. Maybe prepublish script which installs ESLint if the Node.js is new enough. Makefile should then check the version before trying to run it.

[makepanic]

I rebased with some pinned versions which works on all our AppVeyor node versions, so it shouldn't be a problem anymore.

I could revert it for the lint target though.
What do you prefer?

[boneskull]

fine as is for now. thanks a ton!