Adding threadring benchmark.

These benchmarks are just here for convenience for now. Actually putting them
in the eve repo is a bit of a hassle while they're still fluctuating so until
they're stable I'll keep them here.
Adding chameneos benchmark.
First draft processor registry (broken).
Error handling for double-freeing a pid.
Fixing up a few bugs.
Refining a few implementation parts.

Mostly just little rewritings and adding asserts.
Updating benchmark to be in line with others.

Basically this means running the first set of runs then the second.
No longer holding object pointer.

An object pointer used to be fed to the thread creation from the eiffel
side because it wanted one. The only real requirement is that it be an
`eif_access'-able reference. To this we just use a double-reference now.
So far no problems with thsi approach.
Renaming global to processor_registry.

This is the more self-contained version of the previous global.