personalization of newsletters and some tweaks

Hi!

I've made some, at least for my purposes, improvements to the already excellent simplenews module and wanted to share.

I wanted to be able to put !username in the newsletters for all subscribers, (personalized emails) that meant adding an optional name field to the simplenews_subscriptions table and the subscription block form, I also wanted to keep track of how long people had subscribed for, so I added a timestamp field also to the db table. Making this functional required a lot of functions to be modified in the module code. I also made it so email lists can be imported and exported with an optional name like this:

email | name,
email | name,
...

I also wanted to be able to put a custom anti-spam policy message just below the subscribe block form, so I added the option in the admin page for the module. I also got rid of the radio button in the form so the submit bottom just says 'subscribe' and subscribers can unsubscribe via the link in the newsletters.

I've attached the whole module directory with files I've changed for anyone else to use. Enjoy!