Tag versions, add changelog, update package.json

[wvangeit]

We should add a new mechanism to improve version tracking.
We should add also a changelog file.
It should something like this:
if travis passes in master, and it's going to push to pypi, this should happen:

• something like this should be used to create a changelog: https://github.com/vaab/gitchangelog
• the package.json should get the latest version
• these 2 files should be commit automatically into the main repo
• the current version is tagged in the repo
• the tags are pushed to the main repo
• (maybe a github 'release' is created)

There is one chicken-and-egg problem here. The commit will change the version again. An option here would be to 'predict' that version, since it will be the current_version + 1 commit.
Another issue to look at, is how versioneer reacts if all the patch versions are tagged in the repo also.

There is a before_deploy travis block we might be able to use for this.