Add setup functions, matrices and quaternions

examples/dem.py

src/pairs/__init__.py

src/pairs/analysis/blocks.py

src/pairs/analysis/devices.py

src/pairs/analysis/expressions.py

src/pairs/code_gen/cgen.py

src/pairs/ir/accessor_class.py

src/pairs/ir/assign.py

src/pairs/ir/ast_term.py

src/pairs/ir/features.py

src/pairs/ir/kernel.py

src/pairs/ir/layouts.py

src/pairs/ir/lit.py

src/pairs/ir/math.py

src/pairs/ir/matrices.py

src/pairs/ir/mutator.py

src/pairs/ir/operator_class.py

src/pairs/ir/properties.py

src/pairs/ir/quaternions.py

src/pairs/ir/scalars.py