Add better favicons to html

[neely]

Previously had used base64, but should be able to use actual pngs.

Ex.
<link rel="apple-touch-icon" href="images/apple-touch-icon.png" />

[neely]

<link rel="icon" href="strikemap-icon.svg">
<link rel="apple-touch-icon" href="strikemap-icon.svg">
<meta name="theme-color" content="#080c10">