Clean up option --moduleName.

Change moduleName option to [true|false|default] and delegate
default to each module transformer.
Set the default for moduleName to 'default'.
Pass options to ModuleTransformers via arguments rather than module exports.
Create transformOptions view dynamically from local options object.	
Set moduleName false for single file compile, true for bundles.

Fixes #1588
`var x = x = expr`?