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/svgo/Makefile

@@ -0,0 +1,21 @@
+test:
+	@npm run test
+
+lib-cov:
+	@./node_modules/.bin/istanbul instrument --output lib-cov --no-compact --variable global.__coverage__ lib
+
+coverage: lib-cov
+	@COVERAGE=1 ISTANBUL_REPORTERS=text-summary ./node_modules/.bin/mocha --reporter mocha-istanbul
+	@rm -rf lib-cov
+
+coveralls: lib-cov
+	@COVERAGE=1 ISTANBUL_REPORTERS=lcovonly ./node_modules/.bin/mocha --reporter mocha-istanbul
+	@cat lcov.info | ./node_modules/.bin/coveralls
+	@rm -rf lib-cov lcov.info
+
+travis: lint test coveralls
+
+lint:
+	@npm run lint
+
+.PHONY: test