Added a dependency on tharsis.prof.
Added a frame profiler to profile process execution (needed for scheduling)
Added Process execution time to diagnostics.
The writeln debug hack is now @nogc as well.
Increased the required version of `tharsis.prof`.
Doc fixes.
Functionality to attach external `tharsis-prof` `Profilers` to `EntityManager`
Instrumented `EntityManager` code for profiling.