auto_encode should probably pass fully-qualified type- and enum-names

[jbclements]

Per discussion w/ @nmatsakis , the auto_encode framework should probably make calls to the encoder with fully-qualified type- and enum-names. So, for instance, the "name" field in a Some(13) would not be "Some", but rather core::option::Option (or perhaps ::core::option::Option). A similar alternative would be to pass a path along with the name.

I'm creating this issue for use in a FIXME note in the source.

[bstrie]

I can't find the FIXME in question any more. @erickt, is this done?

[catamorphism]

Re-nominating for milestone 5, production-ready -- unless this is actually done?

[alexcrichton]

This FIXME does not appear to be present, nor does auto_encode exist any more (it now manifests itself as deriving(Encodable)).

I'm not entirely sure that we're even still passing around type names in these. This may be more relevant with repr-type things, but @thestinger changed that recently to print full-qualified type names anyway.

From that, I'm gonna go ahead and close this, if others feel different though, feel free to reopen!