ui: Added history of last active symbols to UI and menu (issue 151)

* holding down back or forward button shows list of current back-forward stack
* added narrow button between back and forward to show the list
* added History menu
* moved back and forward actions to History menu
* show chronological list of recently active symbols in History menu

bug id = 151

fortune cookie message = Dein Geschäft wird gut laufen und expandieren.

src/lib/utility/messaging/type/MessageSearch.h

@@ -11,7 +11,8 @@ class MessageSearch
 {
 public:
 	MessageSearch(const std::vector<SearchMatch>& matches)
-		: m_matches(matches)
+		: isFromSearch(true)
+		, m_matches(matches)
 	{
 	}
 
@@ -70,6 +71,8 @@ public:
 		os << getMatchesAsString();
 	}
 
+	bool isFromSearch;
+
 private:
 	const std::vector<SearchMatch> m_matches;
 };

src/lib/utility/messaging/type/MessageToUndoRedoPosition.h

@@ -0,0 +1,24 @@
+#ifndef MESSAGE_TO_UNDO_REDO_POSITION_H
+#define MESSAGE_TO_UNDO_REDO_POSITION_H
+
+#include "utility/messaging/Message.h"
+#include "utility/types.h"
+
+class MessageToUndoRedoPosition
+	: public Message<MessageToUndoRedoPosition>
+{
+public:
+	MessageToUndoRedoPosition(size_t index)
+		: index(index)
+	{
+	}
+
+	static const std::string getStaticType()
+	{
+		return "MessageToUndoRedoPosition";
+	}
+
+	size_t index;
+};
+
+#endif // MESSAGE_TO_UNDO_REDO_POSITION_H

src/lib/utility/utilityString.cpp

@@ -243,6 +243,24 @@ namespace utility
 		return (wsback <= wsfront ? std::string() : std::string(wsfront, wsback));
 	}
 
+	std::string elide(const std::string& str, ElideMode mode, size_t size)
+	{
+		if (str.size() <= size || str.size() <= 3)
+		{
+			return str;
+		}
+
+		switch (mode)
+		{
+		case ELIDE_LEFT:
+			return "..." + str.substr(str.size() - size - 3, str.size());
+		case ELIDE_MIDDLE:
+			return str.substr(0, size / 2 - 1) + "..." + str.substr(str.size() - (size / 2 - 2), str.size());
+		case ELIDE_RIGHT:
+			return str.substr(0, size - 3) + "...";
+		}
+	}
+
 	std::string substrBetween(const std::string &str, const std::string &delimiter1, const std::string &delimiter2)
 	{
 		size_t found_delimiter1 = str.find(delimiter1);

src/lib/utility/utilityString.h

@@ -48,6 +48,15 @@ namespace utility
 
 	std::string trim(const std::string &str);
 
+	enum ElideMode
+	{
+		ELIDE_LEFT,
+		ELIDE_MIDDLE,
+		ELIDE_RIGHT
+	};
+
+	std::string elide(const std::string& str, ElideMode mode, size_t size);
+
 	template <typename ContainerType>
 	ContainerType split(const std::string& str, const std::string& delimiter)
 	{