upcoming/go-package-store: typos/grammer fixes + alternate ending
upcoming/go-package-store: Editing.

As promised, I've carefully re-read my entire post and tried to edit it
to the best of my ability. I'm pretty happy with most parts and have
fixed up a few sections that I knew weren't expressing what I wanted to
say well.
This should be the final version, unless there are any more typos or
other review suggestions.
Merge pull request #57 from shurcooL/upcoming/go-package-store-fixes

Upcoming Go Package Store: Fix typos and editing.