I've added some commits recently which fix support down to node 0.10 - those must be published in the 6.x line prior to merging this.

Merging this will be a semver-major change - it drops < node 4 support, and drops support for eslint v2. In the process, we'll be able to use any syntax and API that node 4 supports, yay!

I also enabled rules requiring template literals instead of concatenation, and autofixed them, both because I think it's a superior approach, and because it illustrates some of the new syntax we'll get to use :-)

(I'll manually keep this rebased and updated as time goes by, so ideally it will always be ready to merge when v7 comes along)