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/underscore/amd/unescape.js

@@ -0,0 +1,8 @@
+define(['./_createEscaper', './_unescapeMap'], function (_createEscaper, _unescapeMap) {
+
+	// Function for unescaping strings from HTML interpolation.
+	var _unescape = _createEscaper(_unescapeMap);
+
+	return _unescape;
+
+});