chore: add CHANGELOG.md and release v 1.0.0

Author: tivie

CHANGELOG.md

@@ -0,0 +1,23 @@
+<a name"1.0.0"></a>
+## 1.0.0 (2015-06-04)
+
+#### Release information
+
+This release updates the extension in order to make it compatible with showdown v.1.0.x.
+However, this version is not compatible with older versions of showdown.
+Since prettify extension was previously bundled with showdown, with versions prior to v 1.0.x, use the bundled version instead.
+
+#### Compatibility
+
+**Compatible with showdown v.1.0.x**
+
+#### Features
+
+* **bower.json**: add dependencies to bower json
+* **package.json**: add dependencies to package.json
+
+#### Breaking changes
+
+* **renamed files**: src file renamed to `showdown-prettify.js`.
+  To update, if your using src files directly, change your dependencies from `prettify.js` to `showdown-prettify.js`
+