Create development branch

[aisthesis]

Having a separate develop branch allows changes to be pushed there while still maintaining a master identical with the most recent published version. Here is what is involved:

• When the next version is complete, branch develop from master.
• Include in README.md at root a section documenting all steps when pushing a new version. Building the documentation is also an important part of this, and that documentation is currently in the makefile for the docs.
• in the future, pull from and push to develop for code changes

[aisthesis]

• https://git-scm.com/book/en/v2/Git-Branching-Branching-Workflows
• https://guides.github.com/introduction/flow/
• http://nvie.com/posts/a-successful-git-branching-model/

It looks like the most common git workflow is to have master always be the decisive version--as opposed to the master -> staging -> release workflow that I've seen elsewhere. We should stick with the standard workflow.

That means that we should create a permanent branch develop that will be decisive between versions. It will be merged into master only when the new version is ready. All user branches should be created from develop and merged into develop.