Merge remote-tracking branch 'upstream/master'
Implement size search
Merge https://github.com/CodaFi/mailcore2
Testing search expressions with size
Merge branch 'Search-Size' of https://github.com/CodaFi/mailcore2
Check for if search expression for size works
Added constant IMAPMessagesRequestKindSize to IMAPMessagesRequestKind, somehow file was not updated after testing with searchExpression changes of CodaFi