Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/papaparse/tests/test.js

@@ -0,0 +1,20 @@
+var connect = require('connect');
+var serveStatic = require('serve-static');
+var open = require('open');
+var path = require('path');
+var childProcess = require('child_process');
+
+var server = connect().use(serveStatic(path.join(__dirname, '/..'))).listen(8071, function() {
+	if (process.argv.indexOf('--mocha-headless-chrome') !== -1) {
+		childProcess.spawn('node_modules/.bin/mocha-headless-chrome', ['-f', 'http://localhost:8071/tests/tests.html'], {
+			stdio: 'inherit'
+		}).on('exit', function(code) {
+			server.close();
+			process.exit(code);  // eslint-disable-line no-process-exit
+		});
+
+	} else {
+		open('http://localhost:8071/tests/tests.html');
+		console.log('Serving tests...');
+	}
+});