Merging in some changes from SVN:
http://plugins.trac.wordpress.org/changeset/733401/issuu-pdf-sync
Change readme.txt to fit the WordPress readme.txt style:
http://wordpress.org/plugins/about/readme.txt
Added license information as advised by the WordPress.org readme.txt validator:
http://wordpress.org/plugins/about/validator/
Added an upgrade notice section as advised by WordPress.org readme.txt validator:
http://wordpress.org/plugins/about/validator/
Added Russian translations by Konstantin Ryabenko.
Removed some spacing.
Updated to version 2.2.4.
WordPress Coding Standards optimizations.
Corrected order of change log.
Added an upgrade notice for v2.2.4.
Removed spacing.
Removed closing PHP tag.
Added some spacing.
WordPress Coding Standards optimizations.
Merge branch 'release/2.2.4'