Enhancements

Performance enhancement. It is now possible to disable some heavy resource operations and achieve better performances (see also #76):
- Correlation checking by turning check_correlation to False (#43)
- Recoded checking by turning check_recoded to False.
Possibility to install using conda
Implementation of a new Boolean variable type (#25)
Add new badges for zeros and highly skewed (#63)
Code refactoring (internal improvement) to split on main modules in 4 modules (#65)
Improve types handling
- types like list, tuple and dict are now officially unsupported until we improve them
- mixed columns are also correctly handled
- New Binary variable type supporting native boolean type and also binary numeric values (#77)
Warnings column names have link to corresponding detail in variables section in order to ease the navigation (#66)
Spearman and Pearson Correlation matrix diagrams added in the report (#83)

Bug fixes

#56 Incorrect calculation for % unique for variables with missing values bug
#11 Avoid to throw an error when calling get_rejected_variables while correlation has not been computed
#68 Avoid to set the matplotlib backend if not necessary