just display a flash message on import ended #5
added new admin page to list imported posts #14
fix thumbnail generation errors #5

- test `scheme` and disable `reject_unsafe_urls` [HTTP
arg](http://codex.wordpress.org/Function_Reference/wp_remote_get#Paramet
ers) before launch download
- throw exceptions on
[importer](https://github.com/Spoon4/slideshare-posts-import/blob/master
/admin/includes/class-slideshare-importer.php) errors