Introducing optional parameter in adjacency lists for lone electron
pairs

The following adjacency list example describes NO2 with the radical 
electron on the nitrogen atom with the following parameters where
numberLoneElectronPairs is new and optional:

atomIndex atomType numberRadicalElectrons numberLoneElectronPairs
bonds{}
1 N 1 0 {2,D} {3,S}
2 O 0 2 {1,D}
3 O 0 3 {1,S}