Maven Repo + Minor Changes to Main File  + Unit Tests

#### Maven Repo
@jvimr Turned the project into a maven project. All that I added to that was the JUnit dependencies.

#### Changes to VerbalExpression.java 
- prefixes, source, and suffixes are now given empty string values at the start of the program for the following reasons:
	1. Allows us to assume in the method add() that source is not null
	2. Allows us to remove methods that call on a blank add (purely for readability reasons, doesn't cut down on code)
	3. Fixes issue where prefixes and suffixes would be null causing a whole slew of errors

- Added updatePattern method so we can remove empty adds so method calls make more sense/readable. updatePattern() just compiles the pattern and updates VerbalExpresion's string pattern.

- Added constructor so updatePattern gets called when object is first instantiated. This allows us to remove updatePattern from both toString and test methods.

#### Unit Tests Ported
I ported the unit tests from the main Javascript repo. The framework is JUnit.