one more optimization

The previous versions stored values as string, so any (even if they are
not used) values being converted into string, and then (if required)
being converted back to float/int/etc. I've changed the mechanism, so
they are stored as QVariant (native value).

Please note that it is possible that this rewrite may cause crash in
some cases (if I've missed smth).

sources/awesome-widget/plugin/awkeys.h

@@ -86,7 +86,7 @@ private:
     // variables
     QVariantMap m_tooltipParams;
     QStringList m_foundBars, m_foundKeys, m_foundLambdas, m_requiredKeys;
-    QHash<QString, QString> values;
+    QVariantHash values;
     bool m_optimize = false;
     bool m_wrapNewLines = false;
     // multithread features