Warn/error names with special characters

This fixes GH-360. It does the following:

* Introduces a standard `NameRegexp` in the `config` package that all names must adhere to.
* Makes it a deprecation _warning_ for resource names to be invalid.
* Makes it an _error_ for module names to be invalid (since no BC).

We can change the warning to an error in the next version.
Fixed