iOS: Be more specific in where we look for object files to rename main

When building under Xcode we can limit the object files search to the
current SDK and debug/release configuration.

Change-Id: Ic405f13f46a594e3ed20d82ca6b84e7e67edebfc
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>
Mention androiddeployqt in changes-5.2.0

The new way deployment is done can be confusing to users of
Qt 5.1 and Necessitas, so we need to mention that it has changed
and point them to the documentation.

Change-Id: I8e9890699f57d6000370c384c52fcb093a917bef
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>