Fix repository name in README.md
Remove token classes for Java operators that are not miniJava operators.

Create a token class UnusedFeature for both UnusedOperator and
UnusedKeyword.
Merge pull request #8 from jspam/004-unused-operators

Remove token classes for Java operators that are not miniJava operators.
Merge pull request #5 from jspam/001-readme-fix

Fix repository name in README.md
Add lexer stub and test for lexing the empty string.