non-exhaustive (but exhausting) list of changes:
* base laid for multiple window support, but will likely require more work to work correctly
* encapsulation of frontend state for proper multi-instance support
* (JIT still needs a fix for the NDS::Current workaround but we can get there later)
* new, more flexible configuration system
* Reorganize namespaces
- Most types are now moved into the `melonDS` namespace
- Only good chance to do this for a while, since a big refactor is next
* Fix the build
