When the code_server is about to purge a module it will now issue
asynchronous check_process_code requests to all processes at once
instead of one at a time. These check_process_code operation can
execute in parallel.

* bjorn/xml-encoding-fix/OTP-11310:
  Change encoding of troublesome notes.xml files to utf-8
  Convert some notes.xml files from latin-1 to utf-8

* ks/hipe_unified_loader-cleanup/OTP-11301:
  Updated primary bootstrap
  Cleanup of the file

Most notes.xml files will be updated in every release and cause
the kind of the problems described in the previous commit.

* raimo/linux-network-namespace-sockopt/OTP-11157:
  Document socket option 'netns'
  Rudimentary test
  Make netns option value a string
  Implement netns for SCTP + bugfixes
  Implement netns option for TCP and UDP
  Implement emulator netns support for TCP and UDP

Consisting of three items:
 - Eliminate uses of is_subtype/2 in specs
 - Change module-local void functions to return 'ok' instead of []
 - Make sure there are no dialyzer warnings with --Wunmatched_returns

* sze/edlin_understand_keys/OTP-11251:
  Added primary bootstrap
  erts: fixed documentation regarding tty and arrow keys
  make edlin understand a few important control keys

* fh/start-all/OTP-11250:
  kernel: fix documentation regarding ensure_all_started endtag
  Updated primary bootstrap
  Add application:ensure_all_started/1-2