MANIFEST.in: Exclude pyc files
MANIFEST.in: Exclude pyc files

Exclude *.pyc files from sdist, since they don't belong to source
distributions.

Fixes GitHub issue #450.

matthiask/django-mptt,matthiask/django-mptt,emilhdiaz/django-mptt,emilhdiaz/django-mptt,watchdogpolska/django-mptt,emilhdiaz/django-mptt,matthiask/django-mptt,watchdogpolska/django-mptt,matthiask/django-mptt,emilhdiaz/django-mptt,watchdogpolska/django-mptt,watchdogpolska/django-mptt