add delivery ack text view to sending voice, video, pic, loc messages
Merge branch 'audio' into easemob-dev
update voice call ui
fix clear group messgaes bug
updaete voice call chat
fix some phones can't recorder voice for first time
update for send voice
fix sometimes recoder video crash
update message adapter
fix send message ui bug
change debug setting
update sendmessage ui
update version to 2.1.0
add media conference call activity
add media conference activity