ENYO-2570: Added .jshintrc, … files to prepare JSHint automatic execution on pull-request submissions.

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>
ENYO-2570: Added jshint as an npm dev dependency.

Enyo-DCO-1.1-Signed-off-by: Yves Del Medico <yves.del-medico@hp.com>
Merge pull request #351 from enyojs/ENYO-2570

ENYO-2570: Added .jshintrc, … files to prepare JSHint automatic execution on pull-request submissions.