Here's an updated version of my lsprof.py module. I fixed a few bugs,
includes the awful reference leak that was present in the previous
version (i.e., the profiler code was keeping a reference to every frame
executed).

I consider the lsprof.py code functionally equivalent to _lsprof. Now, I
am wondering if I should add the features from profile.py missing in
_lsprof, e.g., the bias argument and the calibration code.