Changed default number of threads to 1 instead of autoconfigured value and
added a new `auto` variable which enables autoconfiguration of thread count.
The number of threads used when autoconfiguratio fails was changed from 4 to 1.
The default value of using N threads where N is the number of CPU cores was
not optimal as the possibility of rescheduling was higher the more utility
threads there were. Due to this, N-1 is deemed to be the better autoconfigured
value for thread count.
8d969aadd1