Clean Up riak_object

[hazen]

This key bit of infrastructure was lacking:

• Documentation
• Cleaner allocation interface
• Cleaner addition of links and user metadata and indexes
• Unit Testing

[bookshelfdave]

@javajolt can't automatically merge, can you please rebase?

[hazen]

I merged in the build-cleanup stuff. Sorry these changes were on top of that so it'll have both changes until #42 is merged.

[bookshelfdave]

Functions that have the form:

link->has_foo = RIAK_TRUE;
link->foo = riak_binary_copy(cfg, value);
if (link->foo == NULL) {
    return ERIAK_OUT_OF_MEMORY;
}
return ERIAK_OK;

should set the has_foo value AFTER the memory check, otherwise has_foo will be set when ERIAK_OUT_OF_MEMORY is returned.

[bookshelfdave]

:+1: