Drop support for Node 0.10 and 0.12

[dignifiedquire]

I mentioned this before, the original plan was to support the latest three releases of Node.js and to follow along with the LTS schedule: https://github.com/nodejs/LTS

At the end of the year both 0.10 and 0.12 will have reached end of maintenance, so Karma can drop them safely.

This should happen in a new major release, aka 2.0.

Things to be done for this

• Update docs
• Update engines matcher in package.json
• Update travis and appveyor configuration to move to 4, 6, 7 being tested.

[nickserv]

Note that 0.10's maintenance has already ended (0.12 ends December 31st).

[wesleycho]

How soon should these changes be made? Is the intention to do a release of 2.0 soon after 0.12 support ends? Will there be an interim release beforehand?

[dignifiedquire]

There is no urgent rush to do this, so I would wait until January for a new 2.0 release. We can still do regular minor and patch releases in the meantime as we need them.

[dignifiedquire]

We are ready for this :)

[nickserv]

The latest versions of eslint, lodash, and log4js now require Node >=4. I think it would be a good idea to update soon if possible.

[wesleycho]

When should this be scheduled for?

Should this declared Node 4+ support change also include an internal change utilizing a Node 4+ feature such as a fat arrow or template literal in order to force code to break if the user is not on Node 4+?

[johnjbarton]

Fixed by PR #2825