Disable editting on RETextItem, RENumberItem, RELongTextItem

1. Disable editting on RETextItem, RENumberItem, RELongTextItem

You may need to disable editting on textfield sometimes.

          self.textItem = [RETextItem itemWithTitle:@"Text item" value:nil placeholder:@"Text"];
          self.textItem.disable = YES;

2. Add REFloatingNumberItem

You may need to input floating numbers sometimes, such as cash, bitcoin.

          self.floatingNumberItem = [REFloatingNumberItem itemWithTitle:@"Cash" value:@"" placeholder:@"＄"];