solenoidal reprojection + symbolic array and buffer support

hysop/backend/device/codegen/base/codegen.py

hysop/backend/device/codegen/base/variables.py

hysop/backend/device/codegen/kernels/custom_symbolic.py

hysop/backend/device/codegen/symbolic/expr.py

...ce/codegen/symbolic/functions/custom_symbolic_function.py

...device/codegen/symbolic/kernels/custom_symbolic_affect.py

hysop/backend/device/kernel_autotuner.py

...kend/device/opencl/autotunable_kernels/custom_symbolic.py

hysop/backend/device/opencl/opencl_symbolic.py

hysop/backend/device/opencl/operator/poisson_rotational.py

hysop/operator/base/custom_symbolic_operator.py

hysop/operator/base/poisson_rotational.py

hysop/operator/tests/test_poisson_rotational.py

hysop/symbolic/__init__.py

hysop/symbolic/array.py

hysop/symbolic/tmp.py