Task retrieval

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!