Default Value Previous

Set the default value of a field to the last value inputed to that field by that user.

Right now only works by delibretly setting the default_value_function key to default_value_previous_default_value_function in the instance setting (when creating field via the api or exported field definition via features).
Currently only tested with fields attached to node, has a low likelyhood of working for others, but ya can try.

Waiting to see if cck expands on it's textbox to allow specificy what function is the default_value_function to modules outside of 'list' (what? why is it doing that? Can't find an issue on it).