Fix headers and imports

setup.py

src/lpy_tools/__init__.py

src/lpy_tools/point_sampler/__init__.py

src/lpy_tools/point_sampler/generatePointCloud.py

src/lpy_tools/point_sampler/scan_utils.py

src/lpy_tools/point_sampler/utilities.py

src/lpy_tools/snapshots/__init__.py

src/lpy_tools/snapshots/lscene_snapshots.py

tests/test-snapshots.py

tests/test.lpy