Release version 1.2.0

• Support for OAUTH2/Bearer authentication. Specify bearertoken in credentials when creating Account. Acquiring the
  access token is outside the scope of this library.
• The interface for specifying credentials for an Account changed (arguments to the constructor of Account). The old username/password parameters are deprecated, but still work.

Pre v1.2.0 way of creating an account (still works with v1.2.0):

new Account("example.com", "theUser", "thePassword");

New way to create an account:

// with username / password auth
new Account("example.com",  ["username" => "theUser", "password" => "thePassword"]);
// new: with bearertoken auth
new Account("example.com",  ["bearertoken" => "theToken"]);