Update favicon

[Rio517]

Update favicon to standard mayday.us favicon https://mayday.us/favicon.ico

[steveslotnick]

This should be easy, but unfortunately there is some weird bug when using sails.js and backbone together. The commit that got this working in the core midas repo says "FINALLY got Backbone and Require working with Sails." https://github.com/18F/midas/commit/ada003bd0fefba19d34c032b1d5a2b809f89d0bc

[Rio517]

It looks like midas is just relying on the browser grabbing the default /favicon.ico. I bet if we add an explicit link to our favicon on mayday.us in the layout, it should work in most browsers.

https://github.com/MayOneUS/midas/blob/master/views/layout.ejs#L5

<link rel="icon" href="https://mayday.us/favicon.ico" type="image/x-icon" />