checkpoint for GPU multidim mapping
failing tests on GPU: testDeliteZipWithReduceTuple(DeliteOpSuite), testReduceRows (DenseMatrixSuite)
CUDA fixes
Merge remote-tracking branch 'origin/wip-release' into cpp-fix

Conflicts:
	framework/src/ppl/delite/framework/codegen/delite/generators/DeliteGenTaskGraph.scala
C++ fix: check null in the transfer function
minor CUDA fixes for apps and add option for multidim