Numeric value mapping for tag values

[skipperTux]

For frameworks not allowing strings as values in specific version classes (like the AssemblyVersionAttribute in .NET) it would be nice to have a numeric tag value, something like NTAG, mapping a tag value to a numeric value for the revision:

alpha = 0
beta = 1
rc = 2
post = 3
final = 4

Not sure about the work amount though. Any thoughts?