list_devices() was updated to take an integer rather than a bool
for the wait_to_appear argument. This updates any tests that
explicily passed True/False as the argument to list_devices.
1) Renamed the test to reflect the usage of PEAP
2) Prevented the creation of an extra instance of iwd
3) Refactored to start catching the exceptions and properly
dispose an instance of iwd
4) Switched to list_devices with wait option
Tim Kourt