[Starkit] Error when copying files from startkit to disk (with test cases)

[Vince Darley]

This error will be in the Tcl command tcl::CopyDirectory or the C function 
CopyRenameOneFile (tclFCmd.c), I think.  Not sure which.  Obviously 
something isn't handling the 'force' flag correctly.

A brief reading of the code suggests that tcl::CopyDirectory should always 
over-write if the destination exists (since its caller will already have 
thrown an error if -force wasn't given), but this hypothesis needs careful 
testing.

Vince.