fix type in rdbSaveKeyValuePair() when saving an intset. Don't merge this commit into 2.2 as will not apply cleanly.

save ziplist encoded type as a different type id. Done as separated commit since this is the part that will not merge cleanly in 2.2

fixed color support for test suite. Now colors are shown as long as there is xterm somewhere inside the TERM env var

fixed two diskstore issues, a quasi-deadlock creating problems with I/O speed and a race condition among threads