use less memory as element->span[0] will always be 1; any level 0 skip list is essentially a linked list

Better to increment the version minor number when a VM bug is fixed... it will be simpler to understand what's going on when users will report problems with the INFO trace.

A problem with replication with multiple slaves connectiong to a single master fixed. It was due to a typo, and reported on github by the user micmac. Also the copyright year fixed from many files.

ZRANGEBYSCORE now supports open intervals, prefixing double values with a open paren. Added ZCOUNT that can count the elements inside an interval of scores, this supports open intervals too

Added "withscores" option to zrangebyscore command. Based on withscores support in zrange function, ugliest part was the argument parsing to handle
using it with the limit option.

multi bulk requests in redis-benchmark, default fsync policy changed to everysec, added a prefix character for DEBUG logs

Faster version of the function hashing possibly encoded objects, leading to a general speed gain when working with Sets of integers

faster Set loading time from .rdb file resizing the hash table to the right size before loading elements

Fixed VM corruption due to child fclosing the VM file directly or indirectly calling exit(), now replaced with _exit() in all the sensible places. Masked a few signals from IO threads.

Fixed memory human style memory reporting, removed server.usedmemory, now zmalloc_used_memory() is used always.