Update q param to take list of str

[jonnymaserati]

Addresses issue #82. Tested with the following and it worked:

from newsapi import NewsApiClient
import os

api_key = os.environ.get("NEWSAPI_KEY")

api = NewsApiClient(api_key=api_key)

r = api.get_everything(q=["Wave Inc", "Space Power Technologies", "Emrod"])

Check result in debug console:

>>> r.get('status')
'ok'

[mattlisiv]

Thanks for the update