Multi bulk optimization for creating big objects without copying data is no longer optional, #ifdefs removed. Also debugging messages removed.

to 16k, request buffer size is no longer destroyed when emtpy and large
(better fix needed). Redis clients static output buffer set to 16k as
well.

speed-regression.tcl: move tests, data size, requests in global vars that will be changed via command line options.

speed-regression.tcl script: killing previously tested instance fixed. Don't run if there is already an instance running in the same port.

further optimizations for the multi bulk protocol parsing code when big objects are transmitted to Redis.

sdsIncrLen() / sdsMakeRoomFor() used to avoid copying to intermediate buffer while reading the client query.

sdsMakeRoomFor() exposed as public API. sdsIncrLen() added. Both the changes make it possible to copy stuff from a system call to an sds buffer without the need of an additional buffer and copying overhead.

build: fix sunos build, compile lua with __C99FEATURES__=1

maxclients configuration is now implemented dealing with the actual process rlimits. Setting maxclients to 0 no longer makes sense and is now invalid, the new default is 10000.
See issue #162 for more information.

It is now possible to disable password authentication via CONFIG SET. Thanks to Jan Oberst. This closes issue #171.

If a Lua script executes for more time than the max time specified in the configuration Redis will log a warning, and will start accepting queries (re-entering the event loop), returning -SLOWSCRIPT error for all the commands but SHUTDOWN that remains callable.

Clear the AOF rewrite scheduled flag once an AOF rewrite is triggered. Fix for issue #161, probably fixing 159 as well.