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/test/UtilityStringTestSuite.h

@@ -156,6 +156,31 @@ public:
 		TS_ASSERT_EQUALS(result.at(6), "D");
 	}
 
+	void test_substr_before_with_single_delimiter_occurence()
+	{
+		TS_ASSERT_EQUALS(utility::substrBefore("foo bar", ' '), "foo");
+	}
+
+	void test_substr_before_with_multiple_delimiter_occurences()
+	{
+		TS_ASSERT_EQUALS(utility::substrBefore("foo bar foo", ' '), "foo");
+	}
+
+	void test_substr_before_with_no_delimiter_occurence()
+	{
+		TS_ASSERT_EQUALS(utility::substrBefore("foobar", ' '), "foobar");
+	}
+
+	void test_substr_before_with_delimiter_at_start()
+	{
+		TS_ASSERT_EQUALS(utility::substrBefore(" foobar", ' '), "");
+	}
+
+	void test_substr_before_with_delimiter_at_end()
+	{
+		TS_ASSERT_EQUALS(utility::substrBefore("foobar ", ' '), "foobar");
+	}
+
 	void test_substr_after_with_single_delimiter_occurence()
 	{
 		TS_ASSERT_EQUALS(utility::substrAfter("foo bar", ' '), "bar");