Update versioning scheme

[sunt05]

the current versioning system is based on a manual process of updating the version number in the code and the documentation. This is error prone and can lead to confusion.
we may want to consider using git-tags to manage the versioning.
This would allow us to use the git-tag as the version number and the git-tag message as the release notes.
This would also allow us to use the git-tag to create a release on github.