Use less memory when emitting the protocol, by using more shared objects for commonly emitted parts of the protocol.

setKey(): call the higher level wrapper setModifiedKey() instead of touchWatchedKey() even if currently they are exactly the same.

New script timeout semantics and SCRIPT KILL implemented. SHUTDOWN NOSAVE and SHUTDOWN SAVE implemented.

high resolution expires API modified to use separated commands. AOF transation to PEXPIREAT of all the expire-style commands fixed.

Initial support for key expire times with millisecond resolution. RDB version is now 3, new opcoded added for high resolution times. Redis is still able to correctly load RDB version 2. Tests passing but still a work in progress. API to specify milliseconds expires still missing, but the precision of normal expires is now already improved and working.

FLUSHALL now prevents rdbSave() from resetting the dirty counter, so that the command will get replicated and put inside the AOF. This fixes issue #142

don't process EXPIRE with negative TTL or EXPIREAT with time in the past if we are a slave too (see http://groups.google.com/group/redis-db/browse_thread/thread/5a931fefb88b16d5). Also propagate it as DEL.

They will be expired (and a DEL will be logged) after the loading is done
instead.

Fixed semantics of CLUSTER SETSLOT, SELECT now only denied in cluster mode if selected DB is not 0 so that MIGRATE still works well.