Merge branch 'master' of https://gitlab.tiker.net/inducer/loopy into c_execution

doc/ref_kernel.rst

doc/tutorial.rst

examples/python/hello-loopy.py

loopy/auto_test.py

loopy/check.py

loopy/codegen/bounds.py

loopy/codegen/instruction.py

loopy/diagnostic.py

loopy/execution.py

loopy/isl_helpers.py

loopy/kernel/__init__.py

loopy/kernel/instruction.py

loopy/preprocess.py

loopy/schedule/__init__.py

loopy/schedule/tools.py

loopy/statistics.py

loopy/target/c/codegen/expression.py

loopy/target/ispc.py

loopy/target/pyopencl.py

loopy/target/pyopencl_execution.py