Bump version to 0.2.0

Remove harmless webpack error by keeping react <15.4 in this
version. As a result, the DOM property configs will be required
from `react/lib/`.

Chore:
- Tidy package.json
- Create npm script `clean` and update scripts
- Update README installation instructions
- Fix Travis tests

package.json

@@ -1,6 +1,6 @@
 {
   "name": "html-react-parser",
-  "version": "0.1.1",
+  "version": "0.2.0",
   "description": "An HTML to React parser.",
   "author": "Mark <[email protected]>",
   "main": "index.js",