Fixed over-eager alternation capturing issue.

When an alternation wrapped in capturing parens would capture text with
one alternation choice, but the overall regex failed with that choice,
and a later alternation choice DID result in an overall regex match, the
engine would report both the initial invalid capture and the final valid
capture. For example, the regex, "^(\d\d\d\d|24680)$", when given input
text "24680", would report two captures: "2468" and "24680", when only
"24680" is correct.
Merge branch 'master' of https://github.com/QuickenLoans/RegExpose