Add new YAML dumper with improved readability
Add new YAML dumper with improved readability

By default, the YAML dumper will output lists that are values in a
dictionary flush with the key they are under:
```
key1: value1
key2:
- a
- b
- c
```

This new dumper causes the list members to be indented by two spaces,
improving readability:
```
key1: value1
key2:
  - a
  - b
  - c
```

It can be used by passing the new `IndentedSafeOrderedDumper`,
or any other dumper which includes the `IndentMixin`,
to the `yaml.dump` function:
```
dumper = __utils__['yamldumper.get_dumper']('IndentedSafeOrderedDumper')
yaml.dump(some_dict, Dumper=dumper)
```

saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt,saltstack/salt