This reverts commit e020f75c10410a6943cd055bfa072a2641eab7da.

This reverts commit bd64ad8e15d66e48b36dbe3584315dd5cfc8b59a.

* raimo/new-gen-state-machine/OTP-13065: (52 commits)
  Add section on state filtering
  Promote gen_statem over gen_fsm
  Modify code_change/4 to return CallbackMode
  Use ?NAME macro in examples
  Introduce Fred Herbert suggested additions
  Introduce corrections from Fred Hebert and Ingela
  Use .png pictures instead of .gif
  Write Design Principles chapter
  Fix missing short forms for event timeout
  Do more intricate Fred Hebert doc changes
  Change Caller -> From as suggested by Fred Hebert
  Do documentation improvements from Fred Hebert
  Fix broken documenation reference
  Rename state_timeout -> event_timeout
  Fix most of the system docs and emacs mode
  Change code_change/4 to {ok,State,Data}
  Fixup sharpened test suite
  Sharpen test suite
  Remove the remove_event action and all alike
  Relax caller() type check and cleanup
  ...

Conflicts:
	lib/stdlib/src/gen.erl
	lib/stdlib/src/gen_event.erl
	lib/stdlib/src/gen_fsm.erl
	lib/stdlib/src/gen_server.erl
	lib/stdlib/test/error_logger_forwarder.erl

=== OTP-18.3 ===

Changed Applications:
- asn1-4.0.2
- common_test-1.12
- compiler-6.0.3
- cosNotification-1.2.1
- cosTime-1.2.1
- cosTransactions-1.3.1
- crypto-3.6.3
- debugger-4.1.2
- dialyzer-2.9
- diameter-1.11.2
- edoc-0.7.18
- eldap-1.2.1
- erl_docgen-0.4.2
- erl_interface-3.8.2
- erts-7.3
- eunit-2.2.13
- hipe-3.15
- inets-6.2
- kernel-4.2
- mnesia-4.13.3
- observer-2.1.2
- orber-3.8.1
- public_key-1.1.1
- runtime_tools-1.9.3
- sasl-2.7
- snmp-5.2.2
- ssh-4.2.2
- ssl-7.3
- stdlib-2.8
- test_server-3.10
- tools-2.8.3
- webtool-0.9.1
- wx-1.6.1
- xmerl-1.3.10

Unchanged Applications:
- cosEvent-2.2
- cosEventDomain-1.2
- cosFileTransfer-1.2
- cosProperty-1.2
- et-1.5.1
- gs-1.6
- ic-4.4
- jinterface-1.6.1
- megaco-3.18
- odbc-2.11.1
- os_mon-2.4
- ose-1.1
- otp_mibs-1.1
- parsetools-2.1.1
- percept-0.8.11
- reltool-0.7
- syntax_tools-1.7
- typer-0.9.10

Conflicts:
	OTP_VERSION
	erts/vsn.mk
	lib/test_server/doc/src/notes.xml
	lib/test_server/vsn.mk
	lib/webtool/doc/src/notes.xml
	lib/webtool/vsn.mk