Tagging 2.3.4

git-svn-id: http://plugins.svn.wordpress.org/document-gallery/trunk@1045387 b8457f37-d9ea-0310-8a92-e5e31aec5664
* Added donate link to Document Gallery row in Dashboard plugins index.
* Added migration script to add 'meta' branch with now contains the 'version' field and a new field, 'donate_link', which is dynamically pulled from the README on updates.

git-svn-id: http://plugins.svn.wordpress.org/document-gallery/trunk@1045471 b8457f37-d9ea-0310-8a92-e5e31aec5664