Refactoring: Moved individual node modules to nodes.py
Refactoring: Moved individual density modules to densities.py
Refactoring: Moved individual network modules to networks.py.
Refactoring: Moved individual decision node modules to nodes.py.
Refactoring: Moved decision networks.
Refactoring: Merged factor elimination, particlefiltering in one file, respectively.
Refactoring: Moved individual sampling modules to MCMC.py.
Refactoring: Adapted imports.
Refactoring: Renamed package reasoning, moved XMLBIF reader to io.py
Refactoring: Emptied __init__.py files.
Removed trailing spaces.
Code style.
Made examples and tests work again.
Updated gitignore.