ui: fixed autocompletion issues

* click in autocompletions list causes search
* right arrow for autocompletion
* changed query operator has from '>' to '.' and operator sub from '.' to '+'
* fixed autocompletions to fit to query
and
* fixed spectral layouting endless looping on unconnected node

src/lib/utility/utilityString.h

@@ -33,6 +33,7 @@ namespace utility
 
 	bool isPrefix(const std::string& prefix, const std::string& text);
 
+	std::string toLowerCase(const std::string& in);
 	bool equalsCaseInsensitive(const std::string& a, const std::string& b);
 
 	std::string replace(std::string str, const std::string& from, const std::string& to);