Allow changes to position order on the organisation' people page

This also changes the default ordering to be by the legal_name
of each person, which makes more sense as a default, I think.

This is part of the fix for #659.
Whitespace changes
Consolidate repeated code
Add identifiers to the admin, and as inline to place, person and organisation. Closes #668
Merge branch 'issues/668-identifiers-admin'
Enable tables in markitup
Add table styling to the infopage CSS
Style the homepage markdown correctly
Add example of tables to the sampler
Merge branch 'master' into production