Choose a testing strategy

[raphaelcruzeiro]

Due to the increased complexity of the editor's core and the recent breaks introduced by new bugfixes, it is now time to choose a testing strategy for the project. This task comprises of choosing a test framework and integrating it with the current code base. The documentation should also be updated, instructing the contributors on how to create tests for the new features and bugfixes.

@otaviosoares , we could use your expertise here.

[ilanbiala]

Check out gremlins.js, could be useful for random testing to see if things break. It's not a real testing suite though, you'll need something like Mocha, Chai, or something else to run tests that you define.