Propsed branching change

[Tristan Sloughter]

To streamline development, getting changes into erlware master branches faster, and to cause less confusion with how most people are used to github branching being done for open projects I've proposed we get rid of the use of next branches, like https://github.com/erlware/relcool/tree/next

To do so I've added travis-ci builds that also build Pull Requests. This way pull requests themselves act as the 'next' branch in a way.

Thoughts?