Gets the class out of the global namespace.

Moved over from #3266 in citra.

Optimized messages that were repetitive and added ability for core errors to specify more details optionally.

credit to @Hawkheart for the original idea

* Removes circular dependences (common should not depend on core)

This makes clang-format useful on those.

Also add a bunch of forgotten transitive includes, which otherwise
prevented compilation.

Adds support for threaded pausing so citra doesn't spin wait on pause