Add connect_to_API function to Flask app, connect using twitter keys and tokens.

Insert call to connect_to_API to /display handler.
Connection function returns api object, which is passed into user instantiation.
Import tweepy.
Remove API connection from __init__ in friends.py, add default parameters to __init__

Init now sets self.api and self.CURRENT_USER (both optional parameters)
Twitter API keys and tokens are no longer global vars.

WIP - now I am importing Tweepy into both friends.py and flask_server.py