Implemented Generic select hook for ZOOM (bug #803). This is achieved with

Implemented Generic select hook for ZOOM (bug #803). This is achieved with
the following new functions:
 ZOOM_process_event,
 ZOOM_connection_get_{socket,mask,timeout},
 ZOOM_connection_fire_event_{timeout,socket}.
The existing blocking event handler, ZOOM_event, is a wrapper for the
+ blocking ZOOM_event_sys_{poll,select}.