[gedit-list] show space and tab sybmols instead

[Mikael Hermansson <mike tielie gmail com>]

Hmm would it be possible to add some kind of special symbols in
textview/sourceview that will for example show spaces and tabs as
symbols?

like an arrow for tabs and a round little circle for spaces?

 Sometimes this is good future if youre editing a python file for
example...