add a new data class to represent changes on clones
make sure the fields are clear at the begnning of processing new versions
add DAO for clone modification
add DAO for clone modification to DBManager
[MINOR_CHANGE] update comments
add a field of modifications to DBCodeFragmentMapping
add owner code fragment mapping to DBCloneModification
update clone modification DAO to be able to handle owner code fragment mappings
add a function to get modifications with code fragment mapping IDs
add methods to add modifications
update the DAO for code fragment mappings to be able to handle modifications
implement refreshChildren in CloneModificationDao
update mapping helper to handle new data scheme