This patch adds several warnings for qml code not supported by Qt Quick
Designer.

* WarnImperativeCodeNotEditableInVisualDesigner:
   This warns about imperative code affecting a visual property.
   e.g.: "x = 10;"

* WarnUnsupportedTypeInVisualDesigner:
    This warns about types which are currently not supported.

* WarnReferenceToParentItemNotSupportedByDesigner:
    This warns about things like: "width: parent.width" in
    the root item.

* WarnUndefinedValueForDesigner:
    This warns about visual properties that cannot be evaluated in
    the local context.
    e.g.: "x: somethingNotDefinedInTheLocalContext.x"

* WarnStatesOnlyInRootItemForDesigner:
    This warns about states not defined in the root item.

All the Qt Quick designer related warnings are disabled by default
in Check.

Change-Id: If31a8199fb95dc8bf6ac613634a2e442e436e267
Reviewed-by: Christian Kamm <kamm@incasoftware.de>