Curator failing silently with invalid yaml

I'm using curator 5.8.1.

I tried using the following yaml file:
```
---
actions:

1:
action: delete_indices
description: >-
Delete indices older than 180 days.
options:
disable_action: False
ignore_empty_list: True
timeout_override:
continue_if_exception: False,
filters:
- filtertype: age
source: creation_date
direction: older
unit: days
unit_count: 180
exclude: False
```

It's wrong, look at the comma after the 'continue_if_exception'.
But curator fails silently on it:

```
2020-01-24 11:08:02,962 DEBUG curator.cli run:110 Client and logging options validated.
2020-01-24 11:08:02,962 DEBUG curator.cli run:114 default_timeout = 30
2020-01-24 11:08:02,962 DEBUG curator.cli run:118 action_file: /tmp/infsec.yaml
```

A error message should be returned.

Reproduce the failure with the YAML shown in the issue and start from the curator.cli run path, where the logs stop after the action_file is reported. Trace how the action file is parsed and validated, then verify that malformed YAML produces a visible error instead of ending silently.

Written by the indexing model from the issue text.