Continuation Core and Toolboxes (COCO) Code

moved test of event function value to locate_multi

- we now use scaled estimate of interpolation error for
error test in locate_multi
- added opts.cont.MEVFac for customising acceptance of
multiple events
- corrected evhan for cusp and pitchfork (now includes
error handling)
- fixed bug in locate_events: "touching zeros" are now
treated correctly
- we don't allow strings for function handles anymore
- added example (unfolded) pitchfork

set ignore list

added directory for example pitchfork