Clear field and values when editing the first time

Before, when you click to add a node, it prepopulated with "field" and "value" 
as the values of the node, but you then have to delete the text or double click 
on it before starting to write.

To avoid this, I've added code that detects the first time you hit a field or value, 
and selects all of the text, so you can still read it, but the moment
you start typing, it will delete.