This brings contains a number of fixes including a couple new features.
Most prominently, Libraries API now has support for downloading external libraries for you using Drush. In particular, there is now a drush libraries-download command. In order to support this, libraries need to provide a download file url in their metadata. See hook_libraries_info() for more information.
Please note that you need to clear caches after applying this update!
The most important change of this release is that theme-provided library information now actually works. Themes can implement hook_libraries_info() in their template.php just like modules. This supposedly worked in 7.x-2.1 already but did not work correctly.
Most importantly, Libraries API can now manage the library information for you. The idea is that you declare the library information once in hook_libraries_info() and the simply use libraries_load() to load it. Also see the handbook for more information.
This is the first alpha release of the 2.x branch of Libraries API.
You can do a lot more than libraries_get_path() now, see the libraries.api.php file now shipped with the module. A lot is still unfinished and in flux, but if your use-case is not supported by our API yet, we hope to see you in our issue queue!