API reference added to the documentation, small changes

.~dev.ipynb

dev.ipynb

dev.pyx

dev.pyxbld

docs/Makefile

docs/conf.py

docs/index.rst

docs/make.bat

docs/reference/ab_fit_ref.rst

docs/reference/api.rst

docs/reference/c_funcs/aperture_wp.rst

docs/reference/c_funcs/barcode_profile.rst

docs/reference/c_funcs/ct_integrate.rst

docs/reference/c_funcs/fraunhofer_1d.rst

docs/reference/c_funcs/fraunhofer_1d_scan.rst

docs/reference/c_funcs/lens_wp.rst

docs/reference/c_funcs/make_frames.rst

docs/reference/c_funcs/make_reference.rst

docs/reference/c_funcs/make_whitefield.rst

docs/reference/c_funcs/total_mse.rst