[Qt-creator] Dev: Bumping Qt requirement of Qt Creator 4.0

[Ziller Eike]

In the light of the release of Qt 5.6, I suggest that we bump the minimum required Qt version for Qt Creator 4.0 (and master) to Qt 5.5.

Br, Eike

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Eike Ziller, Principle Software Engineer - The Qt Company GmbH
 
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