To be removed in Erlang/OTP 18

* pf/document-escript-feature-only-present-in-examples/OTP-11827:
  Document an escript:create/2 hidden feature

escript:create/2 accepts a 3-elements tuple containing files and
zip:create/3 options to build a zip file.

Also had to update zip typespecs to allow referral from escript docs.

* vladdu/unicode_parameters_doc:
  Specify that +fn* flags affect even command-line parameters and environment variables

OTP-11818

* vinoski/sys-get-rep-state2:
  remove tuple funs from special process documentation
  fix sys:get_state/1,2 and sys:replace_state/2,3 when sys suspended

OTP-11817

The 'encoding' option of erl_parse:abstract/2 has been extended to
include 'none' and a callback function (a predicate).

The rationale is that a more general means of determining what integer
lists are to be represented as strings may help readability when
generating Erlang code given input in some other encoding than Latin-1
or UTF-8.

Add two new system callbacks Module:system_get_state/1 and
Module:system_replace_state/2 to allow sys:get_state/1,2 and
sys:replace_state/2,3 to operate correctly even if a process is sys
suspended. Modify gen_server, gen_fsm, and gen_event to support the new
callbacks.

If a callback module does not export these functions, then by default the
Misc value (the same as that passed as the final argument to
sys:handle_system_msg/6, and returned as part of the return value of
sys:get_status/1,2) is treated as the callback module's state.

The previous behaviour of intercepting the system message and passing a
tuple of size 2 as the last argument to sys:handle_system_msg/6 is no
longer supported.

Add tests to verify the correctness of sys:get_state/1,2 and
sys:replace_state/2,3 when processes are sys suspended. Add two tests for
modules that implement special processes, one that exports
system_get_state/1 and system_replace_state/2 and one that doesn't.

Much of the credit for this patch goes to James Fish, who reported the
initial problem and implemented much of the fix.

* hb/clarify_encoding:
  Clarify the reference manual regarding source file encoding