LeftOwners and RightOwners can now be used as either disjoint
or overlapping sets of users for encrypting a message. Default
behavior is to set them to Owners given a non-empty Owners set.
One member from each group are required to decrypt the message.
In the passvault, the default type of public key cryptography is
selected via a variable. The core test has been changed where it relies
on RSA specifically to check for the default record type.
