* Modified FOIL_container

* Added unit tests for FOIL_container functions

* Added knowledge_current_best notebook

* Added knowledge_FOIL notebook

* Added knowledge_version_space notebook

* Added images for knowledge_FOIL notebook

* knowledge.ipynb replaced by knowledge_current_best.ipynb, knowledge_version_space.ipynb, knowledge_FOIL.ipynb

* modify knowledge.py

* test commit

* agents.ipynb

* agents.ipynb

* Fixed all the instances of issue #833

* minor fix and cleared change in agents.ipynb

* Added predicate_symbols

* Added FOIL

* Updated README

* Added tests for search.py

* Updated readme

* Removed extra newline

* Fixed seed

* Update README.md

* Added docstring for minimal-consistent-det

* add version-space learner + small fix

* add test for version-space learner + trivial example

* Update README.md

* fix small bug in knowledge.py

If hypotheses was empty, it would fail.

* add knowledge.ipynb

* fix dollar signs

* add image

* Update README.md

* add powerset to utils

* add powerset test

* Create knowledge.py

* Create test_knowledge.py

* add header docstring to knowledge.py

* update learning docstring

* minor edits in knowledge.py