rewrite realtime doc... single dialog is done...group chat is waiting to continue
update doc
update for group chat
update for signature
Merge branch 'master' of github.com:leancloud/avoscloud-doc

Conflicts:
	realtime.md
Added app search rest api.
add last step for signature
change to template appid
add quote
Added search api link to rest_api.md
fix {{}} expression display
md {{}}
fix md
readme
Merge pull request #22 from lbt05/master

v2.6.8
Merge pull request #21 from leancloud/wujun_wp

Wujun wp
fixed merge conflict.