Adding additional arbitrary data to atoms and bonds

Arbitrary data (e.g. JSON object) can be saved into the atom and bond data structures. Methods are g(s)etAtomAdditionalData, g(s)etBondAdditionalData. This page shows also the use of the pseudoMark option, custom marker color circle (markerIconColor), custom bond and atom background colors (setAtomBackgroundColors, setBondBackgroundColors), custom size for atom and bond background coloring.