Increased socket send and receive buffer sizes to 1MB.
Removed configuration of obsolete FD_CLOEXEC socket flag.
Added retries in socket receive to support non-blocking IO
More updates to client and public API to internalize PDUs and intgrate new KineticSession which has a handle to internal instance data.
Merge branch 'develop' into feature/pimpl_api
Incorporated return of KineticStatus for all public API methods for consistency. Made progress on allocation of connections per session, and also allocation of PDUs per operation.