Task retrieval

[adamjreilly]

I had the need to add Task support for something I am doing. I am not sure that an explicit #initialize method is needed for Task, but without the call to reload_meta, I think was getting only the mini version of the resource.

I tried to follow the conventions as I understood them from other data types, and am happy to make any changes necessary to make them fit in better if necessary. I also haven't added any tests because I didn't see them for things like Comment. Willing to add those if I can get some guidance.

Thanks for the great library, I've learned a lot in reading through it!

[adamjreilly]

Forgot I had a link to relevant docs. https://developers.box.com/docs/#files-get-the-tasks-for-a-file