Update index.js to no longer require __dirname

Based on shrhdk#76

Author: incentfit

src/index.js

@@ -4,7 +4,13 @@
 
 import * as opentype from 'opentype.js';
 
-const DEFAULT_FONT = require('path').join(__dirname, '../fonts/ipag.ttf');
+// Browser bundlers might not have path or __dirname. Make DEFAULT_FONT optional
+let DEFAULT_FONT = '';
+try {
+  DEFAULT_FONT = require('path').join(__dirname, '../fonts/ipag.ttf'); // eslint-disable-line global-require
+} catch (e) {
+  DEFAULT_FONT = '';
+}
 
 // Private method