erts: Fix is_map/1 spec
erts: Document map guard functions

* erlang:is_map/1
* erlang:map_size/1
erts: Reduce runtime of test port_SUITE:close_deaf_port

as it fails with timeout sometimes.
doc: Document Maps datatype in reference manual
erts: Fix bug of scheduling a suspended process

This is a race that can cause RUNNING (instead of RUNNING_SYS)
set on a SUSPENDED process. The effect of this race happening is probably
quite benign.

The bug was discovered by process_SUITE:processes_gc_trap on debug VM
crashing on last assert in schedule():

/* Never run a suspended process */
ASSERT(!(ERTS_PSFLG_SUSPENDED & erts_smp_atomic32_read_nob(&p->state)));
erts: Fix bug in test case port_SUITE:otp_5119
inets: Handle all response codes in httpd_util:message/3
Merge branch 'sverk/test-cuddle'

* sverk/test-cuddle:
  erts: Fix bug in test case port_SUITE:otp_5119
  erts: Reduce runtime of test port_SUITE:close_deaf_port
Merge branch 'sverk/suspend-running-race'

* sverk/suspend-running-race:
  erts: Fix bug of scheduling a suspended process
ssl: Add possibility to specify ssl options when calling ssl:ssl_accept
Merge branch 'ia/ssl/accept-with-options'

* ia/ssl/accept-with-options:
  ssl: Add possibility to specify ssl options when calling ssl:ssl_accept
Merge branch 'ia/inets/dialyzer'

* ia/inets/dialyzer:
  inets: Handle all response codes in httpd_util:message/3
doc: Clearify language of user-defined attributes
doc: Descripe Maps type syntax
edoc: Add map/0 as a new predefined type
doc: Add maps to reference manual
doc: Mention map expressions and map guards
doc: Add Maps example for sequential programming
Merge branch 'egil/maps-doc'

* egil/maps-doc:
  doc: Add Maps example for sequential programming
  doc: Mention map expressions and map guards
  doc: Add maps to reference manual
  edoc: Add map/0 as a new predefined type
  doc: Descripe Maps type syntax
  doc: Clearify language of user-defined attributes
  doc: Document Maps datatype in reference manual
  erts: Document map guard functions
  erts: Fix is_map/1 spec
Update preloaded modules