[Bf-python] Changing confusing python console start-up message

[Ken Hughes]

Stephen Swaney wrote:
> Summary:
> 
> Feel free to change the message about the internal interpreter version.
> 
> Importing modules from a version that does not match the internal one
> should be an error.

So should we print an error to the console if we don't import the right 
site?  Or throw an exception inside RunPython whenever the user tries to 
run a script?

Ken