fix gui dead-lock issue when request token
bug fix: parse comments count json failed lead broken issue
enhancement: icon background drawing issue
fix QtConcurrent reverse build issue on OSX
enhancement: change "document" to "note"
update markdown plugin to support more languages
message center rewrite and avatar interface
fix retina drawing issue
同步功能改进，和请求token放在一起处理。有一些需要处理的地方，包括在线程内发送消息会不会有问题？周胜波看看。

快速同步先留下，以后处理。
cached avatar
fix syncing issue
change sync log prefix
update message avatar when loaded
new style messages list view
Fix drawing issue on osx
fix message wrap and size issue
easy drawing
add message filter and open message note
draw list view cached
simplify list view drawing call