fix: spec: running tests in python3 after build
fix get_str() in packagedelta-py
fix pycomp_get_string(), pycomp_get_string_from_unicode()

Actually dereference the pointer passed. Fix prototype and all users.
get_delta_from_evr(): create the python object only when delta exists
remove: packageDelta_new
python3: fix unicode literals

u"foo" is a syntax error in Python3.2.