Coeus core version 0.2.0-alpha

- Added Coeus:Terminate that should be called by user code upon completing the application.
- Added support for directory-level member overrides via a file called "_". Check src/Coeus/Sound/_.lua for details.
- Added Get method to directory objects so that flags can be passed in.
- Updated all internal Coeus module methods to take a "flags" table instead of a "safe" flag. Presently the only flag is "safe".
- Removed Coeus:FullyLoadDirectory in favor of a directory method called FullyLoad.