Page Snippet Inclusion Macro

Allow to transclude part of a resource. This is especially useful to grab information from an SCM server (usually set to a tag, but maybe on a trunk - maybe we could set the version of the product to the space properties and resolve the corresponding SCM tag accordingly?)

• Allow multiple protocols: http, https, ftp, ... but start with HTTP.
• Search for a marker on that page and the end marker.
• If it is XML, allow to specify an ID (we do not want to parse HTML!).
• Use the shortcut-id/space-property infrastructure
• The snippet has to be added to Lucene.
• If the snippet cannot be found, render a fault box instead. These boxes can be found easily.

Also document how to export (if your export the wiki, the users have to have access to the remote servers, too).

Optional

• If the snippet changed, we could add a warning label (not a box, because tags can be removed more easily). A box would need some logic to unmark the problem. To recognize a change, we have to store the MD5 of the snippet with Lucene/AOP and check on rendering.
• A process that finds all macros and renders them in order to find these missmatches (also applies to missing snippets). Otherwise we get only noticed once a user renders the page).