Enable/define language representation of atomic ops

doc/ref_kernel.rst

loopy/__init__.py

loopy/check.py

loopy/codegen/__init__.py

loopy/compiled.py

loopy/expression.py

loopy/kernel/__init__.py

loopy/kernel/array.py

loopy/kernel/creation.py

loopy/kernel/data.py

loopy/library/reduction.py

loopy/preprocess.py

loopy/target/c/codegen/expression.py

loopy/target/cuda.py

loopy/target/ispc.py

loopy/target/opencl.py

loopy/target/pyopencl.py

loopy/tools.py

loopy/types.py

loopy/version.py