Make it possible to specify the parser for BeautifulSoup4

[fumiya5863]

If you have lxml installed, BeautifulSoup4 will set lxml as the default parser, so it would be better to be able to specify the parser depending on the situation.

opengraph/opengraph/opengraph.py

Line 63 in e232256

doc = BeautifulSoup(html)

This is the default setting because we didn't actually do the parser above.

Depending on the environment, the following issue cases may occur due to the above reasons
#37

As a solution, I think it would be a good idea to add a new parser that can be selected in the following arguments

opengraph/opengraph/opengraph.py

Line 28 in e232256

def __init__(self, url=None, html=None, scrape=False, **kwargs):