compile_pattern should not use string.lower() or use re.I flag

[baby5]

python-readability/readability/readability.py

Line 80 in 3cbede6

return re.compile(u'|'.join([re.escape(x.strip().lower()) for x in elements]), re.U)

class or id attributes may have uppercase

[buriy]

You're right. Could you make a PR?

[baby5]

@buriy I have made a PR for this