Warnings, Skips, and Failures

[jasonvarga]

You can now have the command exit with a failure status code, useful for CI deployments.

In your config/statamic/ssg.php you can set whether to fail on errors or warnings (which includes errors).

'failures' => false, // 'errors' or 'warnings'

Here's what you'd see with failures enabled:

With them disabled (the default):

On my terminal, the color of the next prompt is the exit code.
The first command exited with a failure code, so it's red. The second one succeeded, so it's green.

When failures are disabled, you'll see the errors and warnings inline, then a summary.

Closes #70
Closes #71
Closes #72