quick and dirty delete user function

This adds a delete button kinda hidden away: go to admin, then users, then click a user, and the delete button is there. It has a quick JS confirmation against accidental clicking.

This uses plain html because the rails helpers weren't doing what I wanted and I figured I had spent enough time wrestling with them for what's just a quick backend thing to destroy test data so i just did it the easy way and moved on.
Had to lookup <tt>.  It says its not supported in HTML5?  Was this <table> html completely broken in the first place?  I'm just going to merge b/c this doesn't matter for now.