Parser Element and Keyword tests (#199)
Parser Element and Keyword tests (#199)

* Expand Keyword unit test

* Add ParserElement add unit tests

* Add ParserElement sub unit tests

* Add ParserElement mul unit tests

* Add ParserElement Match First unit tests

* Add ParserElement Match Longest unit tests

* Add ParserElement Each unit tests

* Refactor and cleanup
pyparsing/pyparsing,pyparsing/pyparsing