fix unsetting of LDFLAGS for Python 2.4 (popping from os.environ doesn't work, see http://bugs.python.org/issue1287)

don't include pthread library with MKL (because it resides somewhere else, and numpy won't find it in e.g. mkl/lib/intel64)

fix Python support with ictce toolkit by tweaking specified libraries in numpy's site.cfg (refs #268)
clean up IMKL lib defs in toolkit.py, fix some bugs along the way