minor tweaks

Clarifying some (random) things that are incomprehensible to english
speakers who don't live in an American context, or otherwise seem
unnecessarily cryptic
typo

Thanks M. Corlosquet
Documenting release history.
Drafting a releases page.
Added earlier info.
Linked more terms, dated workPerformed.
Added 0.91.
Linked the releases page.
Added IDs and reworded note at footer.
Fixed markup, css, numbering.
Merge pull request #79 from danbri/sdo-releases

Adding a Schema.org Releases history page.
Linked LOV.
Merge pull request #74 from chaals/master

minor tweaks