autowrap: return the actual error reported by f2py/gfortran
fix issue 3715
Fix: N does not throw an exec. when passed a symbol
don't introduce a new function name (run_process)
check for OSError in test_autowrap.py

an OSError is raised when the executable does not exists
add missing with_statement to compatibility.py
added tests
fixed test_erf_f_code test
run_process is superseded by check_output from the compat. module
Merge pull request #2007 from thisch/issue_3715

Issue 3715