Document known client/embedded differences for the Version 10.1 release

The known differences between the Client and embedded driver listed in the seciton

Comparision and/or differences with the Derby Embedded Driver
in the Client spec at:
http://incubator.apache.org/derby/papers/DerbyClientSpec.html

Should be documented for the 10.1 release.

It should also be noted that there may be additional differences that are not documented and in the future the client driver may be changed to match embedded. For example SQLStates for exceptions generated from the client may be changed to match embedded.