editormd.amd.js
function(eventType, callback) {
            var settings = this.settings;
            
            if (typeof settings["on" + eventType] !== "undefined") 
            {                
                settings["on" + eventType] = $.proxy(callback, this);      
            }

            return this;
        }
function(eventType, callback) {
            var settings = this.settings;
            
            if (typeof settings["on" + eventType] !== "undefined") 
            {                
                settings["on" + eventType] = $.proxy(callback, this);      
            }

            return this;
        }
注册事件处理方法
Bind editor event handle

@param   {String}     eventType      event type
@param   {Function}   callback       回调函数
@returns {editormd}                  this(editormd instance object.)