For some reasons, despite being disabled, buttons still call the action
defined as `ngClick`. In the case of the burn progress button, this
results in:
```sh
TypeError: Cannot read property 'device' of undefined
```
Fixes: https://github.com/resin-io/etcher/issues/132
These are files that contain static rules that are not likely change nor
require the advanced functionality that SASS requires.
This is the first step towards an attempt to get rid of preprocessor and
use native supported web technologies.
This screen informs the user that the burn has completed and that the
drive can be ejected directly.
It also provides a button to burn another image without exitting the
application.
Fixes: https://github.com/resin-io/herostratus/issues/41
Currently we say "done" as soon as the progress is equal to 100, however
we don't wait for the drive to be ejected/unmounted.
This commit introduces a new state, called "Finishing..." which is shown
when the progress is 100, but the drive has not been unmounted.
