map: use value semantics for MapLocation

This makes memory management more simple, as not explicit deletion
is necessary.

A rather large commit, because changing QVector<> to std::vector<>
is propagated up the call chain.

Adds a new range_contains() helper function for collection
types such as std::vector<>. I didn't want to call it
contains(), since we already have a contains function
for strings and let's keep argument overloading simple.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/range.h

@@ -98,4 +98,11 @@ int index_of_if(const Range &range, Func f)
 	return it == std::end(range) ? -1 : it - std::begin(range);
 }
 
+// Not really appropriate here, but oh my.
+template<typename Range, typename Element>
+bool range_contains(const Range &v, const Element &item)
+{
+	return std::find(v.begin(), v.end(), item) != v.end();
+}
+
 #endif