Continuation Core and Toolboxes (COCO) Code

if possible; therefore, we:
* changed argument list of all save-, print- and badat- functions
to include one or two charts
* removed field 'sol' completely from opts structure (this is
now much cleaner)
* save_data now returns a chart with updated solution label (.lab)
and point type (.pt_type), this chart is then passed to print-
functions
- user-defined save functions now return variable 'data' instead of
field names
- updated all examples to use 'data' instead of 'sol' where necessary