wpa_supplicant D-Bus interface

[Jouni Malinen]

There is now pretty good coverage of automated hwsim test cases
(tests/hwsim/test_dbus.py and tests/hwsim/test_dbus_old.py) for the
D-Bus interface that wpa_supplicant provides. While implementing those
test cases, I found number of issues both in how the interface is
defined and how it was implemented. The latter I fixed for most parts
and for the former, I tried to handle the cases where this could be done
without breaking backwards compatibility.

In addition to the newly added test cases, there is also a significantly
more up-to-date documentation for the interface in doc/dbus.doxygen. The
latest snapshot of that is here in HTML format:
http://w1.fi/wpa_supplicant/devel/dbus.html

I marked number of places with Bug:/Todo: items where either the design
did not seem to make sense to me or I could not figure out how this is
supposed to be used. Most of these are for the P2P operations and
especially for the case of there being multiple groups.

I'm not completely sure whether anyone is using the current P2P
commands. As such, I did not yet want to change the design or drop the
problematic commands/properties to avoid breaking an external interface.
I'd assume cleaner design could be added while maintaining most of the
existing functionality in more or less working condition. However, I'd
rather not make this any more complex than necessary if no one is using
the current design yet.. In other words, I'd be very much interested in
hearing if someone is using the D-Bus P2P methods/properties/signals and
ideas on how the remaining issues should be handled.

-- 
Jouni Malinen                                            PGP id EFC895FA