Fix contour r2014b

Fixes #380 and #379:
- Filled contours
- Correct colormap 

See e.g. ACID(8,9,10,23): https://www.dropbox.com/s/l8mc01in65lfcbd/R2014b_fix_contour.pdf?dl=0 

PS. R2014b only.
Does this work with plots that contain both a mountain and a valley (e.g. `peaks`)?