Rewrote response reading code, moved INFO and KEYS out of AUTOLOAD

Rewrote response reading code, moved INFO and KEYS out of AUTOLOAD

 * response reading code uses less syscalls with big values: more speed;
 * multi-bulk response fixed: supports mixed items in the response,
   like $ and : in the same response - this happens with SUBSCRIBE
   messages
 * INFO and KEYS have their own methods now: no more if's for special
   cases in AUTOLOAD.

Signed-off-by: Pedro Melo <melo@simplicidade.org>