Merge pull request #968 in FS/freeswitch from ~DINGDING/freeswitch:bugfix/FS-9536-fix-switch_core_hash_delete-return-invalid to master

* commit '9f01830d':
  FS-9536 [core] fix return value

FS-9525 #resolve [Client initiated REINVITE with different audio codec into conference causes choppy audio]

Merge pull request #970 in FS/freeswitch from feature/FS-9543-add-pre-exec-state-change-hooks-to to master

* commit '6a064a95':
  FS-9543 #resolve [Add pre-exec state change hooks to core]

* commit 'e76350df':
  FS-9526 [mod_conference] add deaf sounds

Merge pull request #967 in FS/freeswitch from ~PIOTRGREGOR/freeswitch:bugfix/FS-9527-freebsd-10.3-compile-error to master

* commit '0247c92c':
  FS-9527 [avmd]: Fix MAP_POPULATE on FreeBSD

Remove unsupported flag.

* commit '1c00e64a':
  FS-9533 [mod_conference] add member-enter-sound

Merge pull request #960 in FS/freeswitch from ~SJTHOMASON/freeswitch:bugfix/FS-9424-__byte_order-macro-not-defined-correctly to master

* commit '0c9ab17c':
  FS-9424: Make big endian ifdefs more specific

* commit '03e87faa':
  FS-9518 [mod_conference] allow deaf only command in caller-controls

Merge pull request #959 in FS/freeswitch from ~PIOTRGREGOR/freeswitch:feature/FS-9519-avmd-test-script to master

* commit '8f495672':
  FS-9519: [avmd] Add unit test

Add perl script for testing of voicemail detection.

Merge pull request #950 in FS/freeswitch from ~SJTHOMASON/freeswitch:bugfix/FS-6954-freeswitch-adds-additional-m-audio to master

* commit 'd5b5e8c2':
  FS-6954: Use channel flags to check for proxy media or bypass media

Merge pull request #929 in FS/freeswitch from ~PIOTRGREGOR/freeswitch:feature/FS-9138-avmd-copy-xml-config-to-confdir to master

* commit 'c304eaf3':
  FS-9138: [avmd] Add config to vanilla folder

* commit '0fddb6b0':
  FS-9505 [mod_conference] honor verbose-events in conference-create event

Merge pull request #954 in FS/freeswitch from ~PIOTRGREGOR/freeswitch:feature/FS-9509-subscribe-to-avmd-messages-script to master

* commit '194a2485':
  FS-9509: [avmd] Add perl script subscribing to avmd events

The script will subscribe to avmd events and output them to the console.