Removed direct DBObject.fieldAry references in GanymedeServer

The Test/Repaid Invid and Embedded Object integrity methods
in GanymedeServer now use getFieldVect() on DBObject rather than
directly accessing a DBObject's internal fieldAry.
Improved DBObject encapsulation

Made fieldAry package private rather than protected, permCacheAry
private, and both permManager and myInvid private final.

Removed now useless DBObject(DBObjectBase) constructor.

DBObject.receive() now returns the Invid whose DBObject was
read in.