phpList and Signup module integration

I wrote this "extension" modules that requires phpList, Signup and Event.

The code needs review and further testing. Please let me know what else you guys would be looking for in this module. I wrote it for a client who I am developing a site for. Their site uses the Event and Signup modules to allow users to sign up for events. This module I wrote extends phpList to allow admins to export users who have signed up for both individual events to a list and any user who have signed up for an "event type" to a list. What I mean by an "event type" is a content type. By default with the event module an "Event" content type is created. I have also created other types of events that users can sign up for. The "event type" export will export all users who have signed up for any event of that event type.

WHAT THE MODULE DOES
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Creates 2 pages under phpList in the Admin / Site Configuration / phpList:

Event Type Export:
- Form with 2 select boxes. The first is a drop down list of all node types. The second is a select list of all public lists in phpList.
- Select the event type that users have signed up for that you want to export and the list you want them in then click Export.
- First, all users who have signed up for an event of that type are found (this can be many events that are of the same type) and synched to phpList. Secondly, they are added to the list.

Single Event Export:
- Form with 2 select boxes. The first is a drop down list of all events that people can sign up for. The second is a select list of all public lists in phpList.
- Select the event that users have signed up for that you want to export and the list you want them in then click Export.
- First, all users who have signed up for that event are found and synched to phpList. Second, they are added to the list.

The lists now appear in a users "Newsletters" page and users can unsubscribe from them. This functionality is from the original phpList module but works with this module correctly.

Thank you and please provide me with your code review and changes or additional features. This is the first "module" I have written.

I have attached the zip of the code.

~ Tom