Function to return build or version number

[KirkBrooks]

Knowing the build number would be helpful. In cases where particular code may be dependent on features introduced in recent versions knowing the build number becomes important.

Since NetKit is included in the 4D package it is always there but simply knowing the 4D version is not always enough. Knowing the build would allow me, as a developer, to know if I needed to install a newer version of NetKit in my application.