Update readme with more info

Author: lukeapage

README.md

@@ -1,4 +1,33 @@
-less-plugin-cleancss
-====================
+[![NPM version](https://badge.fury.io/js/less-plugin-clean-css.svg)](http://badge.fury.io/js/less-plugin-clean-css) [![Dependencies](https://david-dm.org/less/less-plugin-clean-css.svg)](https://david-dm.org/less/less-plugin-clean-css) [![devDependency Status](https://david-dm.org/less/less-plugin-clean-css/dev-status.svg)](https://david-dm.org/less/less-plugin-clean-css#info=devDependencies) [![optionalDependency Status](https://david-dm.org/less/less-plugin-clean-css/optional-status.svg)](https://david-dm.org/less/less-plugin-clean-css#info=optionalDependencies)
+
+less-plugin-clean-css
+=====================
 
 Post-processes the css and compresses it
+
+## lessc usage
+
+```
+npm install -g less-plugin-clean-css
+```
+
+and then on the command line,
+
+```
+lessc file.less --clean-css="--advanced --compatibility=ie8"
+```
+
+See [clean-css](https://github.com/jakubpawlowicz/clean-css) for the available command options - the only difference is advanced which we default to false, because it is not always entirely safe.
+
+## Programmatic usage
+
+```
+var LessPluginCleanCSS = require('less-plugin-clean-css'),
+    cleanCSSPlugin = new LessPluginCleanCSS({advanced: true});
+less.render(lessString, { plugins: [cleanCSSPlugin] })
+  .then(
+```
+
+## Browser usage
+
+Browser usage is not supported at this time