Allow &quot; in QQuickStyledText

QString::toHtmlEscaped generates &quot;. QQuickStyledText should be
symmetrical with that function.

Change-Id: I67ea0abe446b5fa1edb53258dca58b84af910e28
Merge pull request #32 from special/master

[qtdeclarative] Allow &quot; in QQuickStyledText