DEBUG RELOAD implemented, and test-redis.tcl modified to use it to check for persistence consistency.

commented the HAVE_EPOLL test in config.h to allow compilation under Linux now that the epoll module is still missing

ae.c now supports multiple polling API modules, even if only ae_select.c is implemented currently. Also adding and removing an event is now O(1).

benchmarking with different number of LRANGE elements. Ability to change the glue output buffer limit by #define

support for writev implemented but currently ifdef-ed in order to understan why I can't see the improvements expected. Btw code provided by Stefano Barbato

multi-bulk reply support for redis-bench, and as a result LRANGE is not tested, providing some number for the tuning of multi-bulk requests performances server-side