Version.txt file. Allows a single stamp to be propagated throughout
the build process.
* Source/Build.Tasks/GenerateAssemblyInfo.cs: Correctly invoke
DateStamp task (need to call Execute() to generate the stamp).
* Source/Build.UpdateVersion/Build.UpdateVersion.csproj: Cleaned up
'Rebuild' target.
Cleaned up 'GenerateAssemblyInfo' task invocation.
Attempted to generate GlobalAssemblyInfo.cs without using a custom
task. Unfortunately, xbuild didn't wish to cooperate.
Remove Version.txt file to update the datestamp.
- DateStamp, which generates a version number based on the current date.
- DelTree which mimics RemoveDir but can delete non-empty directories on xbuild 2.6.x (which only supports empty directories).
- Run which mimics Exec but also captures stderr/stdout.
