Add hasOption method to NodeElement class.

[kukko]

In my case that was a useful method, to check that a select element has an option or not. And I think this will be also useful for others.

[stof]

This will trigger 2 changes of the data of the form, to check whether it has an option or no. that's quite bad as implementation of the check.

[kukko]

Yeah you are right with this. I will rewrite it to don't change the value of the select.