Try a few locations when trying to locate wrapper library
Fix a corner case in wrapper lib finding (reported by Yichao Yu)
Mess around some more to make Py3 find wrapper library
Add some gitignores to make working in Jenkins test env more pleasant
Fix an encoding issue in Py3
Work around Py2.6's lack of ctypes.c_ssize_t
Py2.6 doesn't have int.bit_length--use bitlog2