New parsers and verifiers.

PR includes:
* DoubleParser
* UUIDParser
* EnchantmentParser
* PotionParser
* @Regex verifier
* Unit tests for new features.

* Fix to allow JUnit fail() to correctly fail a test when inside a command method.
* Fixes one of the tests not being annotated with @Test

Not major but could you add brackets `{}` here?