Fix spelling mistakes.

This is an older doc, but I was clearing out old email and found a
message with a few typos mentioned. I couldn't let that go. There were
more substantial items that could be addressed in that message as well.
http://lists.w3.org/Archives/Public/public-webpayments/2011Dec/0034.html
Fix stylesheet loading over http vs https.

Use protocol relative syntax.
Fix links and references.

- Use https://web-payments.org/ base.
- Update to link to secure-messaging spec.
- Use AES vs FIPS-197.
- Fix typos.
Factor out common respec JS.

- Create web-payments-common.js for common respec JS:
- Common preProcess function:
  - This was repeated everywhere.
- Common localBiblio data:
  - Remove JS breakage from old unused "berjon.biblio" access.
  - Much easier to manage similar references in one location.