First cut of rendering match elements

This is currently broken, but a starting point for further work.

src/js/parser/javascript.js

@@ -3,9 +3,15 @@ import parser from './javascript/grammar.peg';
 import Root from './javascript/root.js';
 import Regexp from './javascript/regexp.js';
 import Match from './javascript/match.js';
+import Subexp from './javascript/subexp.js';
+import Charset from './javascript/charset.js';
+import Terminal from './javascript/terminal.js';
 
 parser.Parser.Root = Root;
 parser.Parser.Regexp = Regexp;
 parser.Parser.Match = Match;
+parser.Parser.Subexp = Subexp;
+parser.Parser.Charset = Charset;
+parser.Parser.Terminal = Terminal;
 
 export default parser;