shared library support

[solomonik]

Add capability to build .so lib.

[huttered40]

@solomonik
Extending critter's support to pyCTF, I still think that critter needs to expose two functions at the python level: start(size_t) and stop(size_t,size_t). Otherwise, even if CTF can call start/stop inside its world creation and destruction, the data will add up across the entire program. As an example, there would be no way to use critter to accurately profile two different kernels in the same program if the start/stop only happen when the world object is created and destroyed.

If one simply wanted to profile everything in the entire file, then a pythonized critter::start/stop wouldn't be necessary of course.