tools: append NUL terminator to identifier

CHANGELOG.md

@@ -19,10 +19,11 @@ Changelog
 * tools: added the ability to specify a circle collider in the Sprite Importer
 * tools: added the ability to specify the actor class in the Sprite Importer
 * tools: fixed a crash when entering empty commands in the console
+* tools: fixed an issue that caused the Level Editor to not correctly save a level specified from command line
+* tools: fixed an issue that could cause the Level Editor to incorreclty parse identifiers in SJSON files
 * tools: fixed an issue that prevented some operations in the Level Editor from being (un/re)done
 * tools: fixed an issue that prevented the data compiler from restoring and saving its state when launched by the Level Editor
 * tools: the Data Compiler will now track data "requirements" and automatically include them in packages when it's needed
 * tools: the game will now be started or stopped according to its running state when launched from the Level Editor
 * tools: the Properties Panel now accepts more sensible numeric ranges
 * tools: the Properties Panel now allows the user to modify most Unit's component properties
-* tools: fixed an issue that caused the Level Editor to not correctly save a level specified from command line

tools/core/json/sjson.vala

@@ -226,6 +226,7 @@ namespace Crown
 				s.add(c);
 				++index;
 			}
+			s.add('\0');
 			return (string)s.to_array();
 		}