* New 'Avoiding potential pitfalls' section to be sure we list them all.
* All plain text now wrapped at 80 columns.
* Re-did all the section headings for consistency, and added many `---`
between sections.
* Headers added within the 'Plugin-specific events' section.
* Extend EDCD copyright into 2021 here as well.
* Recommend *against* any attempt at making plugins also work with
Python 2.7.
* setup.py no longer writes appcast files. Mention
edmarketconnector.xml enclosure instead for the url= bit.
* DRY about location of log files, just point to appropriate wiki link.
* Despite what section 4.18 of v28 Journal docs say, the event is
`NavRoute`, not `Route`, and the file is `NavRoute.json`. The array
of hops is still keyed as `Route` though.
* Calls out that both `NavRoute` and `Cargo` events, as passed to
plugins, are augmented with the data from their respective files, and
are not simply the 'bare' event as seen in the Journal.
Python prefers snake_case methods and camelCase classes. This replaces
some camelCase methods with snake_case variants, and has the original
names raise a DeprecationWarning before calling the snake_case versions
A_D had accidentally used 'ClickCounter' for this when their folder name
was 'click_counter'. This lead to using a very bare `logger` which
still used our defined format leading to things blowing up when there
was no adapter to handle `qualname` format string.
timeout_session provides two things, TimeoutAdapter, a HTTP adapter
subclass that automatically adds timeouts to all requests, and
new_session, which automatically creates a request.Session with the
adapter in the correct place.
* Note in monitor.py to update the docs if anything changed about the
'state' dictionary.
* Expand on arguments to all plugin call-ins.
* Particularly what the 'state' diction passed to journal_entry()
contains.
* The contents of the `data` dictionary passed to `cmdr_data()`.
