Add Yokoya_elliptic function to compute Yokoya factors for an elliptic shape.
Add an option to divide by value in read_CST
Add docstrings to read_CST and read_IW2D

Circular and rectangular tapers
Correct module name in tools.py
Add kick factor calculation for quadrupolar wakes (similar to dipolar ones)

To be PEP8 complient:
Lowercase folders
Extended docstrings
Rename and divide some files