Added PIN code example to print_some_pwds.groovy
Wrote first implementation of PasswordChecker.
Added static function to PasswordChecker to get a basic 8-32 characters alphanumeric password checker.
Started coding Groovy test suite for PasswordChecker.
Added tests to Groovy test suite for PasswordChecker.
Corrected a bug in creation of basic PasswordChecker.
Added tests with a more complex password checker.