expose match spans via new method

[matanox]

Enables https://github.com/VerbalExpressions/JavaVerbalExpressions/issues/63. Obviously this is too opinionated, so I doubt you'll merge this. But it is helpful to have this added control, as the original implementation seems to conceal retrieving the spans.

I've no idea why my editor added the superfluous white-space differences in the diff, but these can be easily undone if this gets a green light to merge.

Basically I've added a method getAllGroupSpans exposing the java.util.regex object holding the spans.

[coveralls]

Coverage increased (+0.02%) to 99.359% when pulling 32d0b63b9c65c070dcf97e6f51d0b6de253663ef on matanster:master into f311b15312d02601b14998b35d900f604c512b4c on VerbalExpressions:master.