logic: rewrote messages handling token activation for correct restoring on undo

* saving search query to undo stack with MessageSearch
* saving node and edge with name to undo stack with MessageActivateNode and MessageActivateEdge
* added FeatureController that handels distribution of MessageActivateTokens
* clearing views when refreshing or changing project
* clearing undo stack when changing project
* added StorageCache derived from StorageAccessProxy

src/lib/data/StorageCache.h

@@ -0,0 +1,20 @@
+#ifndef STORAGE_CACHE_H
+#define STORAGE_CACHE_H
+
+#include <map>
+
+#include "data/access/StorageAccessProxy.h"
+
+class StorageCache
+	: public StorageAccessProxy
+{
+public:
+	void clear();
+
+	virtual std::vector<Id> getTokenIdsForQuery(std::string query) const;
+
+private:
+	mutable std::map<std::string, std::vector<Id>> m_queryToTokenIds;
+};
+
+#endif // STORAGE_CACHE_H