Added support for array type responses

[MrTam]

Another one I needed - support for Arrays.

DRS doesn't make any attempt at the moment to discern if a view returns an array of Serializer objects. This is problematic when used with swagger-codegen, as APIs which are supposed to return lists of objects don't say that they do, and codegen expects a single object response.

I did see a similar PR #404, but this has been open for several months with no activity and I needed this for my own purposes now.

What this PR does that the other does not, is push inspection into the introspection layer. In addition, viewset methods named list are automatically made into array responses (as they always are with DRF). I've taken the concept of applying 'many' to the YAML docstring stanza as well, to allow FBVs and other detail / list routes in viewsets to work.

I've also added an expanded information section in misc.rst, with cross-referenced expansion on the many yaml attribute in yaml.rst.

Any questions, give me a shout.

[marcgibbons]

Great - thank you!