Implement beginnings of script import and parsing with validation but
not execution.
First pass at a script module implementation for "import module ns=script"
Cleanup creating modules with goal of checking first if the module is
defined not after creating it.
Begin normalizing return values from functions and commands to
ReturnValue
Rework imports and modules to take URL's instead of streams.
Consistantly store the calling module in modules
rework parsers to use Readers instead of streams