start refactoring regional extrema computation
Merge branch 'master' of https://github.com/ijpb/ijpb-plugins
Update regional minima and maxima to minimise allocated memory and number of implemented methosd
create enum for extrema types
Start implementation of 3D regional extrema using algo
Fix floodfill3D, make minima and maxima 3D use generic algorithm
labeling methods now uses methods in FloodFill class