Removing generated files from version control (adding to .gitignore)
Fixed project

- updated to Errai 3
- fixed Guava version (14 is incompatible with CDI on the server)
- removed commented code blocks that were obscuring class structure
- Made the App class non-abstract
- properly added click handler to button
- reintroduced the @PostConstruct method that builds the UI
Merge pull request #1 from jfuerth/master

Fixed up project