Improve representation of Standards on Overview page

[CynthiaParr-USDA]

http://www.tdwg.org/standards/

• [ ] Replace Date Published with release date and version number
• [ ] Replace Status column with indication of whether standard is ratified or not.

Additional tasks:

• [ ] Remove statuses from http://www.tdwg.org/standards/status-and-categories/
• [ ] Decide if we keep categories?

[peterdesmet]

• Release date/number: where can we find this information? Is it worth to add (and maintain) that info? https://github.com/tdwg/infrastructure/issues/1#issuecomment-129847205
• @gkampmeier, do you know which standards are officially ratified?