privatemsg 6.x-1.3

This security release fixes SA-CONTRIB-2010-080 - Privatemsg - Cross Site Scripting. Also contains a few bugfixes, better indexes to improve performance and more tests for improved stability.

Changes since 6.x-1.2:

• #782956 by Berdir | benone: Fixed admin can't delete other users messages.
• #788254 by Berdir | gold: Fixed can't apply tag to messages in inbox.
• Updated Hungarian translation
• #832708 by Berdir | BenK: Added tests for blocks.
• #832738 by Berdir | BenK: Added tests for preview button
• by Berdir: fixed php notices in tests
• #850094 by Michelle: Updated author pane integration
• #871668 by James Andres: Fixed localised URLs in pm_email_notify tokens.
• #869448 by sirkitree, Berdir: Fixed checking if user options should be saved.
• #820238 by Berdir: Added improved indexes on {pm_index}, {pm_tags} and {pm_tags_index}
• #855730 by andypost | Berdir: Fixed invalid HTML in author pane integration.