Designate the redis service as "redis".

This makes it consistent with the GET probe.
Updated the redis scripts portrules.
Extract and publish more information about redis.

  * Get OS
  * Get redis version (and set it to port.version)
  * Get architecture (and set it to port.extraversion)
  * Make and set an application CPE
Added safe fd_set operations.

Only FD_SET and FD_CLR were available. Added a FD_ISSET equivalent.
Implemented them as static inline instead of macros for consistency.

These functions abort() if the FD number is higher than FD_SETSIZE
(except on windows where no check is performed).