code: function(event, callback) {
          //  To learn how the event system functions, see the comments for Crafty._callbackMethods
          var i, e;
          for (i = 0; i < this.length; i++) {
              e = entities[this[i]];
              if (e) {
                  e._unbindCallbacks(event, callback);
              }
          }
          return this;
      }
docs: @
  #.unbind
  @comp Crafty Core
  @kind Method
  
  @sign public this .unbind(String eventName[, Function callback])
  @param eventName - Name of the event to unbind
  @param callback - Function to unbind
  
  Removes binding with an event from current entity.
  
  Passing an event name will remove all events bound to
  that event. Passing a reference to the callback will
  unbind only that callback.
  @see .bind, .trigger