[MAINT] Clean up repository structure

[monkeyman192]

Currently the master branch is completely unused, and the development branch is the primary branch.
I think we should merge development into master, and then the current development branch can be used for actual development for each release.
The releases can be made when we are happy with the state of the development build.

On top of this, the release versioning will change a little bit.
Previously we had basically every release as a 'pre-release'. Now that we can determine exactly what classes have changes across version differences, this 'pre-release' concept makes less sense. So I think we should instead make the pre-releases commits to the development branch when there are continual changes (such as those right after a game update), and then proper releases occur when the development branch is merged into master`.
We will still continue to tag builds for release as not every commit to master will necessarily require a new release to be made.

Finally, we need to delete a number of stale branches.