Export enhancements

Placeholder for notes on Export Enhancements.

Extend the Extension:Collection to provide an API
Basic Use Case: Be able to use the collection extension from the cmd line.

Interface (list of function from Collection.php)

 * CollectionAddArticle
 * CollectionRemoveArticle
 * CollectionAddCategory
 * CollectionAddChapter
 * CollectionRenameChapter
 * CollectionSetTitles
 * CollectionSetSorting
 * CollectionClear
 * CollectionSuggestAction (ban, add, remove, undo)
 * CollectionGetBookCreatorBoxContent
 * CollectionGetItemList
 * GetMWServeStatus

irrelevant functions (i.e. interactive mode only):
 * CollectionGetPopupData

Add Collection extension support to dumpHTML, and dumpBackup
Use case: Allow for easier export of portions of a wiki.

Tasks

 * Add --collection= flag to each script

Add dumpHTML and dumpBackup support for Collection
Use case: Allow users to export HTML and XML using the Collection interface.

Tasks

 * Remove the article count limit for dumpHTML/dumpBackup formats
 * Add support for adding a category, without expanding the category's article list

Provide parsed & semantically annotated XML of article text (dumps & API)
Use case: Make it easier to reuse the data. This was the #1 recommendation of the Wikimedia Strategy Offline Task Force.