Update base.py

# Passing a hostname in the referer field causes problems with some indexers using CloudFlare and SSL. As the RFC states the Referer field is an optional field only to be used Uri's not typed in the boowser field, I've chosen to comment out the line.

If this field was added for compatibility with other websites, an alternative could be to pass the full URL instead of just a hostname, but this doesn't make much sense as referer.

headers['Referer'] = headers.get('Referer', url)