keep full stop outside parenthesis

Andrej asked for 3 distinct pull requests: {microtype, full stop inside quotations, full stop inside parenthesis}. I had forgot the last one so here its.
My rationale for this regexp is this: parenthesis delimit a sentence so the last period doesn't need a full stop at the end because it's already terminated by the right bracket. But the sentence  where the subsentence inside the parenthesis appear needs to be terminated, to mantain the difference between something like 'When i met John (he's always late) he was wearing...' and 'I met John yesterday (he's always late). Later i've also met...'