logic: search ui performance optimization

* replaced the implementation of the search index. the search index now uses a search-trie. edges have gates that can be used to check if a character can be matched when following the edge.
* SearchMatches now have a text and a list of NameHierarchies that share this node (instead of Ids, so that nodes must be found by names (which makes sure that SearchMatches are still valid after refresh).
* when parsing a project's description the CodeController now looks for NameHierarchies instead of SearchNode names to find ids of linked elements.

src/lib/utility/utility.h

@@ -5,6 +5,7 @@
 #include <deque>
 #include <set>
 #include <time.h>
+#include <unordered_set>
 
 #include "boost/date_time/posix_time/posix_time.hpp"
 
@@ -30,6 +31,9 @@ namespace utility
 	template<typename T>
 	void append(std::set<T>& a, const std::set<T>& b);
 
+	template<typename T>
+	void append(std::unordered_set<T>& a, const std::unordered_set<T>& b);
+
 	template<typename T>
 	std::vector<T> toVector(const std::deque<T>& d);
 
@@ -76,6 +80,12 @@ void utility::append(std::set<T>& a, const std::set<T>& b)
 	a.insert(b.begin(), b.end());
 }
 
+template<typename T>
+void utility::append(std::unordered_set<T>& a, const std::unordered_set<T>& b)
+{
+	a.insert(b.begin(), b.end());
+}
+
 template<typename T>
 std::vector<T> utility::toVector(const std::deque<T>& d)
 {