git hf tag - create per-branch 'build' tags

[stuartherbert]

A request from David Brown

• git hf tag creates a tag called '/', which can be used for building dev / overnight builds from
• is an incrementing integer that is unique to each branch
• when feature, hotfix or release branches are finished or deleted, the branch's build tags are also deleted
• build tags created on develop and support branches will persist
• build tags cannot be created on the master branch