Use single-precision

examples/dem.py

runtime/contact_property.hpp

runtime/pairs_common.hpp

runtime/property.hpp

runtime/read_from_file.hpp

src/pairs/__init__.py

src/pairs/code_gen/cgen.py

src/pairs/ir/cast.py

src/pairs/ir/lit.py

src/pairs/ir/math.py

src/pairs/ir/matrices.py

src/pairs/ir/quaternions.py

src/pairs/ir/scalars.py

src/pairs/ir/types.py

src/pairs/ir/vectors.py

src/pairs/mapping/keywords.py

src/pairs/sim/comm.py

src/pairs/sim/domain_partitioning.py

src/pairs/sim/grid.py

src/pairs/sim/interaction.py