Replace README table with list-table

The table within "content page meta data" wasn't rendering because one of
the headings was misaligned. Prevent this mistake from happening again by
converting them to list-table items, which should be easier to maintain.
Indent code for TOC example in README.
Link syntax in README should be rst not md.
Change README links from anon to named.
Merge pull request #21 from alphagov/readme_formatting

README formatting