#5 Implement the PERFORMANCE_SCHEMA interface

[Jonathon Coombes]

Implement the PERFORMANCE_SCHEMA interface for threads, mutexes, file io etc. to enable fine-grained detailed analysis through standard MySQL methods. This task will essentially migrate the performance monitor (pmon) feature that was in the original Solid engine into the standard tables used the MySQL PERFORMANCE_SCHEMA engine.

[Jonathon Coombes]

It will also provide extensive capabilities to test and fine-tune the solddb engine.