1.2

This PR adds:
add - method to add another regex builder to current regex 
add - unnamed group method and shortcuts for capture* methods
rft - **non backward compatibility** - make Builder constructor package-private
rft - **non backward compatibility** - change multiply method same as in original JS implementation
add - oneOrMore, zeroOrMore and atLeast methods

In tests:
rft - replace assertTrue and assertFalse with assertThat with matcher
add - one more complex example