Improved plugin description and tags.
Fix #1044: itemprop="associatedMedia" should not be added if the post does not have any images.
Add metadata to attachment pages.
Updated function comments.
Edited amt_get_the_excerpt() so to force the generation of the excerpt for attachments from $post->post_content
Use different function to get the post types on which the metabox should be added.
Basic metadata is added to attachments.
Process Twitter Cards for image attachments.
Moved functions for Basic, DC, OGP and TC to separate modules.
Moved Schema.org to module and made several improvements.
Refactoring
Fixed bug: $post_body was not added for attachments we do not process.
Process DC correctly for image, video, audio.
Added 'metadata' to REL_DIRS in make_release script.
Updated make release script.
Updated readme.txt
Added commented out code.
Fixed bug with release script.
Fixed bug in `return` statement.
Added more comments in DC module