code: function login(params,cb) {
  		debug('login', params);
  		return request('login',params)
  			.then(function(data){
  					user = data;
  					debug('user', user);
  					return user;
  				})
  			.nodeify(cb);
  	}
docs: Logs into Todoist via email and password. Necessary to get token
  for authenticated requests
  @alias module:node-todoist.login
  @param  {Object}   params 	Object literal containing email and password.
  @param  {Function} [cb]   	optional callback
  @return {Promise|callback}	Returns a promise or invokes a callback
  @example
  ```js
  // promise style
  todoist.login({email: email, password: password})
  .then(function(user){
  console.log(user)
  },
  function(e) { console.error(e); });
  
  // callback style
  todoist.login({email: email, password: password}, function(err,user){
  if(err){
  console.error(err);
  return;
  }
  console.log(user);
  });
  ```