Add ability to resend confirmation emails

````irc
<bendem> could be nice to have a "you confirmed subscription" on https://tenjava.com/subscribe with a "resend" button if you didn't
````

We also:
* Update robots.txt to stop search engines trying to subscribe to newletters
* Stop ABP (or rather the social media list..) blocking 'twitter' **icons** of all things to block
* Clean up code generally