Added support for non-integer version numbers

This commit adds support for non-integer version numbers (e.g. v2.1).

I've added another test/example to the test project to demonstrate intended usage, in this case  api/v2.1/Hello maps to the VersioningTestApp.Api.Version2_1.HomeController using the default settings.

Note that periods in the version number are translated to underscores in the namespace to ensure a valid namespace token is being built.