Begining of implementing sources with new functions

 * Changed 'addUnitChild' to addParentChildConnection
 * Changed 'removeUnitChild' to removeParentChildConnection
 * Deleted unused comments in C++ source
Added 'getUnitTos', 'getUnitFroms', 'addFromToConnection', 'removeFromToConnection' functions with tests
Refractor on 'getUnitsChildren' -> 'getUnitChildren' and 'getUnitsParents' -> 'getUnitParents'