oc: monkeypatched NGImap4Connection class from sope

To improve fetchUids method so we can retrieve uids in batches.
Otherwise we will face an error 'too long request' kind
oc: NGImap4Connection:fetchUids don't delete RawResponse
oc: NGImap4Connection:fetchUids changed error messages
Merge branch 'master' into jgarcia/fix-fetchuids
Merge pull request #56 from Zentyal/jgarcia/fix-fetchuids

Be able to fetch mails from very big folders