Replace jshint+jscs with eslint

[markelog]

JSCS is now unmaintained, in order to provide full compatibility with ESLint, ESLint team identifying most popular JSCS presets and providing for them ESLint replacement.

Grunt config is one of them, sharable config for it is now published - https://github.com/markelog/eslint-config-grunt

Would you like to switch to it?

[vladikoff]

Thanks for the issue! @shama what are your thoughts on this?

[shama]

SGTM!

[markelog]

Okay, cool, will try to send PR soon