Added OpenACC scan benchmark, with naive algorithm.
Merge branch 'openacc' of https://github.com/spaffy/shoc into openacc

Conflicts:
	src/openacc/level1/scan/Makefile.in
	src/openacc/level1/scan/Scan.cpp
	src/openacc/level1/scan/epmpi/Makefile.in
A build system update.