Solving many bugs when using artisan

Previously, many artisan commands didn't work well (try *routes*, *list*, or *migrate:make*), due to incorrect use of the Popen class. These have been fixed. Changes of #25 are included in this pull request as well.

Output from artisan commands is now always shown in a panel, and no distinction between successful execution or failure is made; in either case, the response from artisan is displayed in the panel.