Use STL algorithms instead of Qt's deprecated ones

Change-Id: I58262ef9be93f36465a64f79d0c71a5c83e0ad9e
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Avoid gcc warnings

<variable> defined but no used
and
<variable> may be used uninitialized in this function

Change-Id: Ic4ae4afc31113bddd3a6c0ede742f67d22f1c444
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Optimize QOrganizerManagerEngine::addSorted()

...by using std::upper_bound instead of linear search.

Change-Id: Ia990126e7e3fc1ead9b111fd80a5f5329b516d12
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Emit valueChanged on appending a recurrence detail

Change-Id: Ibdbcb73602909c0ce9e12cf579a83730e814d7d7
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>