Added extensions support for co_min and co_max. All tests pass with gcc 4.9.3!
Added extensions support for co_min and co_max. All tests pass with gcc 4.9.3!

sourceryinstitute/opencoarrays,zbeekman/opencoarrays,sourceryinstitute/opencoarrays,zbeekman/opencoarrays,jerryd/opencoarrays,jerryd/opencoarrays,jerryd/opencoarrays,sourceryinstitute/opencoarrays,zbeekman/opencoarrays