MediaWiki:Flow-compare-revisions-header-header/qqq

Header for a page showing a "diff" between two revisions of a Flow board header. Parameters:
 * $1 - the title of the Board on which this header sits. Example: User talk:Andrew
 * $2 - the username of the author of the header
 * $3 - URL to the Board, with the fragment set to the post in question
 * $4 - URL to the history page for this post