Update readme.md to match current project state

When running through the exercises in this project, several changes had to be made to be able to get the application running correctly.

* Correct syntax in an `ng-class` declaration
* Add missing documentation for creating the `app.css` file
* Correct paths in html for `bower_components`
* Add `bower_components` path to `.gitignore`
* Correct dependencies in `bower.json`
* Update call for `Math.uuid()` to be `PouchDB.uuid()` to reflect changes made to the PouchDB library