升级ueditor到1.2.6版本

将ueditor升级到1.2.6版，对backspace/Del 键进行友好支持
Merge branch 'master' of https://github.com/SwordBearer/MyStage
Revert "升级ueditor到1.2.6版本"

This reverts commit e3241ac3cafbb7c23ed97a414c7d94e69386c472.