nanshe -> nanshe/nanshe: Moved nanshe into nanshe/nanshe.
__init__.py: Made top level nanshe a module.
spams_sandbox -> nanshe/spams_sandbox: Moved spams_sandbox into nanshe.
synthetic_data -> nanshe/synthetic_data: Moved the module synthetic_data into nanshe.
tests: Corrected all paths to reflect the movement of modules.
synthetic_data/synthetic_data.py: Corrected import paths.
nanshe/advanced_image_processing.py: Corrected import paths.