API Deprecated CMSMain->publishall()
API Deprecated CMSMain->publishall()

The current implementation doesn't scale,
and due to the proliferation of versioned objects
no longer fully works (e.g. doesn't publish all files).

Fixes https://github.com/silverstripe/silverstripe-cms/issues/2406

silverstripe/silverstripe-cms,silverstripe/silverstripe-cms