Changed the name of the global config file.
Added the ability to specify the config search path using the EMK_CONFIG_DIRS environment variable.
Added '$emk' placeholder to refer to the emk directory (where emk.py lives) in paths (will be substituted by emk.abspath).
Made it so that emk.module_paths can contain relative paths; these are resolved whenever a module is loaded based on the current directory (from the scope).
Made it so that import_from can contain relative paths like emk.module_paths.
Made it so that emk.current_dir reflects where the code was loaded from for config and project files.