encoding/gob: should report if a name is registered or not.

[gopherbot]

by brady@orchestrate.io:

It would be nice to have a logical function to go with gob.Register() that reports back
if an object is actually registered. This would help establish if encoding of a given
object is actually going to be readable on the other end or not.

I attached a terrible, poorly written and completely untested conceptual patch to show
my intentions.

Attachments:

1. gob.patch (1806 bytes)

[ianlancetaylor]

Comment 1:

Labels changed: added repo-main, release-none.