Tweak Atmel Studio VSIX extension script output filename to contain the release version.

git-svn-id: http://lufa-lib.googlecode.com/svn@2586 d5102386-fcda-11dd-9fdb-3debd5008f28
Update extension XML format to match latest XDK schema.

git-svn-id: http://lufa-lib.googlecode.com/svn@2587 d5102386-fcda-11dd-9fdb-3debd5008f28