Bio.Application should close /dev/null handles

$ python3.4 -W all test_Application.py
test_echo (__main__.TestApp) ... ok
test_echo_capture_both (__main__.TestApp) ... ok
test_echo_capture_neither (__main__.TestApp) ... ok
test_echo_capture_stderr (__main__.TestApp) ... ok
test_echo_capture_stdout (__main__.TestApp) ... ok
test_echo_file_both (__main__.TestApp) ... ok
test_echo_file_same (__main__.TestApp) ... ok
test_echo_file_stderr (__main__.TestApp) ... ok
test_echo_file_stdout (__main__.TestApp) ... ok

----------------------------------------------------------------------
Ran 9 tests in 0.063s

OK