Add default value for maps:get
Enable tests
Add docs and test for maps:get/3
Test Tweaks
observer: Fix range check

Avoids wxWidgets assert if the table is empty
observer: Destroy the wx env

Ensure that the server exists on close, even though linked to the test process
observer: Let wx create statusbar

wx can not catch the delete of the status bar if
it have not created it, which might cause a crash.
inets: httpd - Reject incorrect large request lines early
inets: httpc - update test suite framwork to adopt to change in httpd
inets: httpd - Behave well on not so long but wrong request lines
inets: Prepare for release

Do application restart as old soft upgrade was not correct
ssl: Move init
Replace traffic-related log reports with no-op function calls

The former were a little over-enthusiastic and could cause a node to be
logged to death if a peer Diameter node was sufficiently ill-willed.
The function calls are to diameter_lib:log/4, the arguments of which
identify the happening in question, and which does nothing but provide a
function to trace on. Many existing log calls have been shrunk.

The only remaining traffic-related report (hopefully) is that resulting
from {answer_errors, report} config, and this has been slimmed.
Don't count messages on arbitrary keys

That is, don't use a key constructed from an incoming Diameter header
unless the message is known to the dictionary in question.  Otherwise
there are 2^32 application ids, 2^24 command codes, and 2 R-bits for an
ill-willed peer to choose from, each resulting in new keys in the
counter table (diameter_stats).

The usual {ApplicationId, CommandCode, Rbit} in a key is replaced by the
atom 'unknown' if the message in question is unknown to the decoding
dictionary.

Counters for messages sent and received by a relay are (still) not
implemented.
Make example code quiet

The output could make it impossible to use the shell. Counters returned
diameter:service_info/2 can be used to check for expected happenings.
Make example server answer unsupported requests with 3001

As it should. The previous discard (surely) pre-dated being able to
return {answer_message, 3001} from a handle_request callback.
Simplify example server

In particular, remove the unnecessary list-or-record answer.
Merge branch 'dgud/observer/tests/OTP-11949' into maint

* dgud/observer/tests/OTP-11949:
  observer: Let wx create statusbar
  observer: Destroy the wx env
  observer: Fix range check
  Test Tweaks
  Enable tests
stdlib: Fix indentation of maps doc
ssl: Add ssl options to listen options tracker