Skip the failed node when falling back
php_stream_gets is a char* return, not int
Added READONLY and READWRITE RESP for future slave failover logic
KEYS command

Keys should never be used in production, but this implementation
allows the use of KEYS in such a way that you can call it normally
and it will look through all of the known masters and return the
whole keyspace.

We might want to implement this only as an option (even at compile
time) as it's very dangerous to run on large keyspaces.