Made it possible to clone an EmptyVector and get an editable Vector.
Reworked gasharl GASHBuilderTask to take advantage of mods to DBObject.getFieldValuesLocal()

We no longer need to check to see if DBObject.getFieldValuesLocal()
returns null, because it will now return an EmptyVector if a vector
field is not present in a given DBObject.
Simplification of gasharl userCustom to take advantage of non-null DBObject.getFieldValuesLocal()