If you just strip items in breadcrum you would end up with empty item in your list. You can either do as shaktimaan suggested and then use
breadcrum = filter(None, breadcrum)
Or you can strip them all before hand (in html_doc):
mystring = mystring.replace('\n', ' ').replace('\r', '')
Either way to get your string output, do something like this:
','.join(breadcrum)