直接删除内容为空的p标签(<p></p>)，否则会被转换为<p><br/></>
直接删除内容为空的p标签(<p></p>)，否则会被转换为<p><br/></>

升级编辑器导致问题（3.5.5->4.1.2）：使用新版编辑器编辑旧版编辑器发的文章时，会无故出现很多空行。
thinkerchan/kindeditor,Youraiseme/kindeditor,Youraiseme/kindeditor,thinkerchan/kindeditor,liufeiit/kindeditor,liufeiit/kindeditor,Youraiseme/kindeditor,waltcow/kindeditor,liufeiit/kindeditor,kindsoft/kindeditor,waltcow/kindeditor,thinkerchan/kindeditor,laoshu133/kindeditor,laoshu133/kindeditor,waltcow/kindeditor,laoshu133/kindeditor,laoshu133/kindeditor,kindsoft/kindeditor,kindsoft/kindeditor,liufeiit/kindeditor,kindsoft/kindeditor,waltcow/kindeditor,Youraiseme/kindeditor,thinkerchan/kindeditor