Investigate the applicability of inline classes to koma

[kyonifer]

Now that inline classes look slated for kotlin mainline (experimental in 1.3-M2), it would be very useful to implement Matrix<T> with inline classes to eliminate any overhead using koma might have had over using the underlying libs on each platform. It appears the feature currently supports a single wrapped property and interfaces (but not abstract bases), which could work for Matrix. There are some backends where a single thing isnt enough currently (e.g. native wants both a pointer to memory and a length) but we can probably refactor a bit to make every implementation wrap a single object.