I added the Spanish translation of the app. The laser.pot file is included as a template for other translators.
I had to include the paths to the data/ui/*.blp folders in the POTFILES.in file to properly track the strings inside, otherwise only the gettext strings in the .py scripts would be translated.
I also modified a bit the importing of gettext in the main.py, sidebar.py and window.py. That is because the gettext.install('laser', localedir) line in laser.in is enough to make all further imports of gettext to alias _("some text")into gettext calls. With this change, the credits of the translator appear on the "about Laser" dialog.
Hailings from Mexico, and I love your app. Three CDs ripped to FLAC and counting!