Catch all mutagen constructor exceptions

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
PEP8 fixes for blacore package

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
Don't set default icon name in BlaMainWindow again

The default icon name is now set in blaplay/blagui/__init__.py so
refrain from setting it again in BlaMainWindow.

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>
Fix regression in mp4.py introduced in commit...

3d4966a0694afd3040cb58967316a9164044a68e

Signed-off-by: Niklas Koep <niklas.koep@gmail.com>