There's no reason to allow direct access to the unique_ptr instance. Only
its contained pointer.

This removes explicit checks sprinkled all over the codebase to instead
just have the SW rasterizer expose an implementation with no-ops for
most operations.

These helpers aren't really part of the kernel, and mem_map.cpp/h is
going to be moved there next.

This commit fixes several kernel object leaks. The most severe of them
was threads not being removed from the private handle table used for
CoreTiming events. This resulted in Threads never being released, which
in turn held references to Process, causing CodeSets to never be freed
when loading other applications.

Implements unrotated planar YUV 4:2:0 -> RGB24 conversions in Y2R.
Currently only the Y (luma) channel is used, so the results don't
contain color. This will be added in a later PR at some point.

This is enough to get all currently know Moflex videos to decode. (Some
don't display on-screen due to seemingly unrelated reasons.)

Thanks to @archshift for doing the initial implementation which I
cleaned up and then fixed the 8x8 block mode.

Aero Porter was throwing an "Invalid Handle" fatal error without this.

Involves making asserts use printf instead of the log functions (log functions are asynchronous and, as such, the log won't be printed in time)
As such, the log type argument was removed (printf obviously can't use it, and it's made obsolete by the file and line printing)

Also removed some GEKKO cruft.

There is no documentation available on this function, but we set the result to false as a stub.
This allows Super Little Acorns to move all the way in game with pp3c.