Separate searches for to, cc and bcc fields.
Furthermore, search with uids now supported.
Changed IMAPSearchKindUids to IMAPSearchKindUIDs to comply to naming conventions
Incorporated comments from CodaFi
mDate in searchExpression is not copied
Minor changes on bracket usage
Removed mDate from searchExpression, now using mLongNumber only
Changed SearchKindCC and SearchKindBCC to SearchKindCc and SearchKindBcc and related code as well
Merge pull request #487 from pfennema/master

Separate searches for to, cc and bcc fields and uids