Removing some redundant links from footer.

- Blog, Feedback, Forum and other links which are elsewhere on the page
- Unmaintained social network pages
- DuckPAN link (that page is cute, but not very useful)
Actually removing feedback link. Removing GitHub from social category.

Maybe duckduckhack link would be useful?
Moving chat link, removing other links.
Removing user counts, moving other links to a single line.
Removing user_counts call from root controller.

Leaving the sub in place in DDGC - could be useful in an admin page.
Invalidate session on successful register to prevent POST replay.
Reverting to 3 column layout with links fr DDG, DDH and DDGC

Thanks @moollaza for heads up on bad links.
Temporarily removing privacy link pending review.
Do not perform entity filtering on msgid.

These aren't presented, should never have markup and it breaks matching.

Subtext: I am an idiot.
Merge pull request #211 from jbarrett/no-entity-msgid

Do not perform entity filtering on msgid.
Merge pull request #204 from jbarrett/clean-footer

Clean up the footer
Merge pull request #210 from jbarrett/invalidate-register-sessions

Invalidate session on successful register to prevent POST replay.