Doc: Link to Enginio from All Modules page

Adds a link to Enginio (Qt Enginio) to the list of
add-on modules for Qt.

Task-number: QTBUG-38264
Change-Id: If0a9c7272ef8442b9e7ae366e04347ffed3e0342
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Doc: Added platform and porting notes for iOS

Discuss deployment and publishing to App Store for
Qt for iOS apps.

Add a brief porting guide, similar to the one for
Android.

Task-number: QTBUG-37490
Change-Id: I7e7ba4037694cf092dcff27811d841611a417d6b
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>
Doc: update scalability topic

Add info about Qt Quick Controls and Layouts,
attached Window and Screen property bindings,
file selectors, and loaders.

Change-Id: I50a90ab9b356dbe986980b15462eae9530000d2b
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>
Doc: command line tools need not be installed separately

The compiler and other necessary parts of the tool chain are found
automatically from the Xcode installation (since Qt 5.2).

Change-Id: I74e962d16aed0ca2a0eed13b701fdfe24495702a
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Doc: Various fixes to Enginio related links.

-Added the other Enginio depends variables.
-Updated name of Enginio.

Task-number: QTBUG-33360
Change-Id: Ica6f7f7ba89740ac610d27e839ae08fed81ada6a
Reviewed-by: Sergio Ahumada <sahumada@blackberry.com>
Bump MODULE_VERSION to 5.3.1

Change-Id: Ieaa48683efd68ca690a947a42928eae5ac193c67
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Merge remote-tracking branch 'origin/release' into stable

Change-Id: I71194401c53ced7854a57cbfbf8c3a9f52ef209e