Update copyright dates and make licenses consistent

[traveller42]

I figure this should only be done by Dave.

I don't know the requirements and what can/should be changed. However, you make the statement that this is released under the MIT license, but all the code still references the AGPL.

[davepeck]

@traveller42 Ah, yeah. Originally when I shipped this it was all AGPLv3 but I decided that was stupid. Agreed that I need to fix this one.