COMP: Turn off OpenMP by default
ENH: Abutting and non-abutting partitions

Added option to the ExtentPartitioner such that
it can generate abutting and non-abutting partitions.
By default partitions will be abutting, unless,
SetAbutting( false ) is called on the partitioner object.
BUGFIX: Fix interval split

Interval split was always assuming that the extent is starting
from 0. Also, restructured some of the code to simplify it and
make it easier to read.
ENH: Add method to compute extent intersection
ENH: New stream-counting kernel...

New openmp kernel to compute the number of streams