* 【修改】selectstart 事件未解绑导致的内存泄漏

fix issue: Performance problem in zTree init with 1k nodes  when you add exhide.js (Thanks:  https://github.com/sarxos)

fixed issue: if don't use 'exedit' package, the removeNode() method will can't trigger the 'beforeRemove' and 'onRemove' callback.

fixed issue:  if the count of drag nodes is more than maxShowNodeNum, will change some node's  selected state.

fixed issue: The setting's data is wrong which in zTree's method.  Example: checkNode and updateNode...
这个 bug 会导致 设置为 radio 且 radioType=‘all’ 时，checkNode、updateNode方法出现异常