Fix tests so nose finds them

Most test collectors expect modules named test_*.py. Some also skip files
with execute bits set
Replace all calls to os.getlogin() causing "Invalid argument"

- But only when there's not a terminal, such as w/ Jenkins
Merge pull request #101 from jerdfelt/tests

Fix tests so nose finds them
Fix unit tests for trigger.changemgmt. (fixes #115)
Fixed tests for NetDevices (fixes #114)

+ Added debug logging to:

  - sample autoacl (conf/autoacl.py)
  - trigger.acl.autoacl
  - trigger.acl.db
  - trigger.netdevices

+ Updated test data in test/data (autoacl.py, settings.py)
+ Updated tests for trigger.acl.db that were affected by
  updated test data.
+ 'setup.py test' now overloads settings.py
+ Added new function for testing captured output to tests/utils
  package
Get custom importlib from trigger.utils vs. native (fixes #119)