Adding accessibility text to the download link on site stats page

Bug 750301

Change-Id: Ie0b0ac8b7f500b4ba417c71b5e36aab066b3223a
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>
Changed alert popup to warn message (Bug #1379086)

If you add a page by drag/drop it adds a warn for each time due to it
being a one item only transaction

If you add one or more pages by checkbox/submit it gives a digest of
the pages changed in the warn message

Change-Id: Ifccccca2c8de9fe4b1a4c2919a290c68f594dff4
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>