JavaScript: Port JSDoc parser to Java.

Author: Max Schaefer

javascript/extractor/src/com/semmle/js/ast/SourceLocation.java

@@ -21,6 +21,10 @@ public SourceLocation(String source, Position start) {
 		this(source, start, null);
 	}
 
+	public SourceLocation(SourceLocation that) {
+		this(that.source, that.start, that.end);
+	}
+
 	/**
 	 * The source code contained in this location.
 	 */