Algorithms: Introduce helper Utils::equal

Takes a member (function) pointer and a value and returns a functor,
that takes a instance of the mfp's class and returns whether it's equal
to value. Sounds complicated, but is a common pattern that is easy to
understand.

Change-Id: Iaaeb90488d34ddfd6940dadd4c66705381198fee
Reviewed-by: Nikita Baryshnikov <nib952051@gmail.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/qtsupport/exampleslistmodel.cpp

@@ -544,11 +544,8 @@ void ExamplesListModel::updateQtVersions()
         // try to select the previously selected Qt version, or
         // select examples corresponding to 'highest' Qt version
         int currentQtId = m_exampleSetModel->getQtId(currentIndex);
-        BaseQtVersion *newQtVersion = Utils::findOr(m_qtVersions,
-                                                    0,
-                                                    [&currentQtId](BaseQtVersion *version) {
-                                                        return version->uniqueId() == currentQtId;
-                                                    });
+        BaseQtVersion *newQtVersion = Utils::findOrDefault(m_qtVersions,
+                                                    Utils::equal(&BaseQtVersion::uniqueId, currentQtId));
 
         if (!newQtVersion)
             newQtVersion = findHighestQtVersion();