Improved performance / bug fixes

.diff-table was not found in a pull request.
table.file-diff did exists though.
Using both for optimal compatibility.

Instead of concatenation HTML, which has the
potential side effect of disabling Github's
functionality, I switched to insertAdjacentHTML.
Merge pull request #1 from Rob--W/patch-1

Improved performance / bug fixes
version bump 0.0.2
Add Collapse/show of discussions at PR.

Version-bump Chrome extension
Added links to extension in the Chrome Web Store and
(Greasemonkey) user script on userscripts.org