Enhanced Batch Communication with the c-tree Server

For enhanced performance, a c-tree batch modification has been made to reduce the number of bytes sent by a client application to the server when a partial key request is made to the BATSET() call. Now, instead of sending the entire PKEYREQ structure to the server, only the fixed state variables (the 14 byte PKEYREQ prefix) plus the significant bytes of the target are sent to the server. Without the modification, ctSIZE(PKEYREQ) bytes were sent (including MAXLEN key target bytes) regardless of the number of significant bytes.

This change is client-side only. The server normally recreates a full-size PKEYREQ block when the request block is smaller than ctSIZE(PKEYREQ).