v1.4.12 @ 2017-07-17
###Feature
- [sdk] Modify format of delivery ack and read ack
- [sdk] Will auto reconnect and send the messages didn't sent when user send messages offline
- [sdk] WebIM support multiple devices, add join chat room event
- [sdk] Add "from" attribute for delivery ack and read ack
- [demo] Add test case of rest interface
- [demo] Upload file function for IE8 compatible in sdk/demo.html
###BugFix
- [sdk] Backward compatible for IE8
- [sdk] Force not to send read ack to user self
- [demo] Fix the bug of creating public group
- [demo] Will show a message with "mute" when the mouse hover on the group mute icon
- [demo] Quote sdk from cdn in demo.html
- [demo] Correct the offline message amount
- [demo] Change window.history.pushState into window.location.href
- [demo] Change window.location.href = xxxx into href.hash
- [demo] Show the available operations to administrators