(core): make material resource file handling project independent
Summary
When having resource.cfg files which reference to materials are loaded, they are prefixed with the working dir. As this is done in a sight file, when working on a sight-project, the prefix corresponds to sight install dir, although the files are in the project-specific path.
Steps to reproduce
Create/use an application that relies on sight and loa specific ogre configurations (materials, shader, et...) through resources.cfg.in files.
Possible fixes
Provide the name of the module which loads the resources file and use it to get the module path, instead of the working dir.