Add test case to showcase the `module_name` bug

`module_name` does not work in modules when called inside a function.
Fix `module_name` bug
Merge branch 'fix-module-name' into develop
Add test cases for module file search
Add infrastructure for module file path retrival

Add function to retrieve a module’s base directory.
Implement `module_file` function

Implement `module_file` function which retrieves a valid, usable path
for a file stored relative to a module. This implements #9.
Merge branch 'module_file' into develop