The BUILD_FLAGS, which is for ticket 2411, isn't in tor yet so it shouldn't
yet be in torctl either. This looks like it will be a comma separated list,
but until it's added to the spec we shouldn't depend on that.

Avoids repetitive constructors among new style events and parsing the
positional/kw arguments if they won't be used.

Using the new style for GUARD events, also fixing a minor bug where the
nickname attribute might be left unset after init. Tested this by deleting the
state directory and restarting tor.

Using the new style for BUILDTIMEOUT_SET events, also adding support for its
TIMEOUT_RATE, CLOSE_MS, and CLOSE_RATE parameters.

*This is not tested* - I didn't figure out a method for triggering
BUILDTIMEOUT_SET events (tried client usage and removing the state
directory/reinitializing but no luck)

Using the new style for ADDRMAP events. These events have both quoted and
non-quoted values breaking positional and keyword parsing, so keeping the regex
parsing.

This expands the event to include the ERROR and GMTExpiry attributes. This was
tested by visiting sites with TBB and printing out the ADDRMAP results.

Using the new style for NEWDESC events. This isn't using the positional or kw
pattern so effectively this is just moving the body parsing into the event.
Tested by attaching to a new tor instance to get NEWDESC events.

This one isn't actually using the new style since the events aren't of the
positional or keyword pattern. I'm just adding the empty positional and kw
args so this doesn't need to become a special case later.

Using the new style for BW events. Tested by attaching to a TBB instance and
exercising the event.

Using the new style for STREAM_BW events. Tested by attaching to a TBB instance
and exercising the event.

If a colon was missing from the target field then the stream event would leave
its port unset. I'm not sure how to exercise this so this change is untested.