Instances of $applicationId vs. $applicationid

[torreytooj]

Throughout seemingly all of this library, the Amazon App ID is defined in either the variable or a property called "applicationId". I noticed some areas where it was called "applicationid" instead, as well a few instances where it was missing as an argument:

IntentRequest.php
Line 9/10 - Missing $applicationId as 2nd argument in __construct function.

Request.php
Line 94 - Missing $this->applicationId as 2nd argument in new Request class creation.

These were reported in my Drupal 8 error logs while I build an Alexa integration app. I am new to this library though, so if I am incorrectly reporting this as an issue for some reason, please let me know so I can correct this.

[deltafactory]

Also seeing the lowercase version defined in line 20 of /Request/Request.php

[danstreeter]

@Izion has fixed quite a few of these in the following commit https://github.com/Izion/amazon-alexa-php/commit/14ec0df829d20849e3e203b6808b2f2199d1cc97