fix up omissions/errors in foundation meeting text

[kat]

(via Peter Timmins)

• call it Foundation meeting rather than Foundational
• include Craig Thomler and Leanne O'Donnell (Blueprint for Free Speech) as attendees-inadvertently omitted

[kat]

and updated slug - https://opengovernment.org.au/2016/01/25/australian-open-government-partnership-foundation-meeting/ (any links to this elsewhere?)