Add Travis CI support for core tests #144

[lazywithclass]

Added the badge to the README.md and created a travis config file.

I followed the guide for contributions, but I'm not really sure I did everything correctly about this passage:

rebase your PR branch on top of upstream develop before submitting the PR

Could you please explain it briefly?
What I did was git pull $remote develop and git chekout -b from it. I think I need another step, but it's not clear to me.

[syl20bnr]

The rebase is only for the case when you have multiple commits in the PR.

That's great ! Now I have to take the time to code the tests :-)
Thank you 👍

Cherry-picked into the develop branch, you can safely delete your branch.

[lazywithclass]

I've seen that the badge in the README is still in the unknown state, are you having problems with that?
I've checked right now on develop and the build gets triggered fine in my account.

I'm now going to have a look at #110, let me know if there's something else I should know.

[syl20bnr]

@lazywithclass I did not activate Travis CI integration for the repo.
#110 is assigned to me but help is welcome, I'll try to make a first batch of tests for configuration-layer.el this week-end. So if you want to add some tests you can start with spacemacs-mode.el. The git related functions could be a good start. Thank you !

[lazywithclass]

Ah that's perfect then. I was worried it had some problems.

I can have a look at the git functions in spacemacs-mode.el, sure.