ComboBox and cell factories

[mick.fleming]

Hi Jonathan,

 > My preference is strongly towards approach 1,
I prefer option 1 too, as I'd like the default ComboBox button to fall 
into line
with whatever styling is applied to the rest of the app, without having 
to care
what that styling is.


 > If it is not set, we should use the default 'toString' cell
For bonus points I'd handle the case where the string runs into the 
ComboBox arrow
by truncating the string with ellipses.


regards,
mick