Block robots

Adds the copy_default_layout method that copies application.html.erb from generator to app/views/.

Check [#16](https://github.com/mrhenry/lalala-ng/pull/77/files#diff-666db87bdc72a013121807d35cedac50R16) up to  [#20](https://github.com/mrhenry/lalala-ng/pull/77/files#diff-666db87bdc72a013121807d35cedac50R20) in `lib/generators/lalala/install/templates/application.html.erb` for what this is all about.