Getting Consumer And Secret Keys

Asks the server to send the consumer and secret keys for the registered
twitter app on dev.twitter.com to user afterwards.

it was chosen not to be hardcoded since sometimes twitter for rare
reasons suspend the tokens and/or transfer the tokens to another app
source, so changing from the server takes no time and be invisible to
the user otherwise, if it was hardoced the app will crash and you have
to wait for apple approval for the update