Add --exe flag to nosetests in Makefile to search executable test files
Add --exe flag to nosetests in Makefile to search executable test files

Otherwise, if a user changes the permissions on their .py files,
the nosetests may not detect those tests.

enochd/RMG-Py,enochd/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,pierrelb/RMG-Py,chatelak/RMG-Py,nyee/RMG-Py,comocheng/RMG-Py,nickvandewiele/RMG-Py,comocheng/RMG-Py,pierrelb/RMG-Py,nickvandewiele/RMG-Py