* Add Workflow with Lint and Test (#3)

* Add Linter Workflow

Add pylint and flake8

* Fix linting errors from pylint

* Fix minor bug

* Extract PaperIDs to struct

Paper allows for multiple and optional ids.
Main paper id (from S2) is mandatory

* Add Tests to Workflow

* Add CollectorByTerms (#2)

* Add CollectorByTerms

* Add Tests for Collector by Terms

* Add Test for SemanticScholar entrypoint

* Update Readme

* Improve formatting and docstrings

* Fix typing errors

* Fix lint and test workflow strategy

* Fix workflow

* Release 0.1.1

* Execute Workflows on PRs to dev

* Improve workflow descriptions

* Add Expander by References  (#5)

* Add Expand By References

* Add tests

* Update Readme

* Fix minor bug with tests

* Improve test coverage for references

Clean test cases

* Update lint style

* Add Expander by Citations (#7)

* Add citations to Paper model

With tests

* Add get citations to S2 provider

* Add Expander

* Add examples

* Add ToString to collectors, expanders, and filters

Add abstract __str__ to all components base class

* Fix CollectorByTerm bug

* Bootstrap WriteToCSV callbacks (#6)

* Bootstrap WriteToCSV callbacks

* Fix minor bugs

* Improve code quality

* Add rejected papers

* Update Readme

* Include module in setup.py

* Improve Comments

* Improve callbacks (#8)

* Change Callbacks interface

Focus on single actions: callback methods now reflect individual actions (e.g. expanding a single paper) rather than the bulk actions (e.g. expanding a group of papers to another group of papers)

* Fix minor bugs

* Define Callbacks to log iteration

* Fix dependency problem

* Implement callbacks on expander

* Release 0.1.2