added docstrings everywhere

binarycpython/__init__.py

binarycpython/core/__init__.py

binarycpython/tests/extra_tests.py

binarycpython/tests/main.py

binarycpython/tests/python_API_test.py

binarycpython/tests/test_c_bindings.py

binarycpython/tests/test_custom_logging.py

binarycpython/tests/test_distributions.py

binarycpython/tests/test_functions.py

binarycpython/tests/test_grid.py

binarycpython/tests/test_grid_options_defaults.py

binarycpython/tests/test_hpc_functions.py

binarycpython/tests/test_plot_functions.py

binarycpython/tests/test_run_system_wrapper.py

binarycpython/tests/test_spacing_functions.py

binarycpython/tests/test_stellar_types.py

binarycpython/tests/test_useful_funcs.py

binarycpython/utils/__init__.py

binarycpython/utils/functions.py

binarycpython/utils/grid.py