Allow for brach names to start with reserved names

[tgbarnett]

The current implementation of GitVer has a specific behavior for branches called master
Unfortunately the way that this is implemented it is for branches that start with master which means that masterfix has the same rules applied (though fixmaster would be treated differently.

I think that masterfix and fixmaster should be treated the same (i.e. not the same as master)

[asbjornu]

Closing as #1273 is merged.