Restructure sub-modules

See #37 (closed) for details.

Sub-modules

The following sub-modules remain:

• hotopy.holo (former hotopy.phase merged with hotopy.propagation)
• hotopy.tomo (merge of hotopy.tomo and hotopy.astra)
• hotopy.image
• hotopy.datasets
• hotopy.utils (merge of hotopy.fourier, hotopy.xray, hotopy.utils, hotopy.io)

Sub-modules support top-level imports

(Most) Sub-modules allow convenient imports from their respective top-level, e.g. from hotopy.image import GaussianBlur, from hotopy.holo import simulate_hologram etc.

Closes #37 (closed).

hotopy/holo/_ctf.py

@@ -85,7 +85,7 @@ class CTF:
     GPU reconstruction with homogeneous object assumption and two-level regularization. Note, that with
     ``betadelta > 0`` the regularization of the low frequcies (first alpha entry) can be omitted.
 
-    >>> from hotopy.phase import CTF, Constraints
+    >>> from hotopy.holo import CTF, Constraints
     >>> imshape = holograms.shape[-2:]
     >>> ctf = CTF(imshape, fresnel_nums, alpha=[0, 5e-2], betadelta=1e-3, device="cuda")
     >>> rec_phase = ctf(holograms).cpu().numpy()  # gather reconstruction from GPU to CPU and wrap as NumPy ndarray.