Add a 'method trace' mode

[alex-davidson]

For a specific thread, trace X stack frame push/pops, or trace stack frame push/pops for X seconds.

Would be very useful for determining exactly which stack frame (deep inside the .NET Framework itself) was causing an infinite loop, or whether it was actually the socket read which was blocked forever.

For bonus points, allow logging of parameters and return values on each frame change too.

[alex-davidson]

This will require use of the profiling API. Profiler must be unmanaged, so a C++ COM library will be required. When attaching, this should be identified by CLSID; does this mean it needs registering with the system? (Makes sense from a security PoV). FunctionEnter and FunctionLeave are first-class profiler concepts so tracing these events should be easy.