Make the web app relocatable (#2)
Make the web app relocatable (#2)

Rather than hard-coding the hostname and directory for the icon and start_url,
use a relative URL so that we can host the app in different subdirectories and
servers without having to customize the web app manifest each time.

Signed-off-by: Dan Scott <2591e5f46f28d303f9dc027d475a5c60d8dea17a@coffeecode.net>
onepopcorn/forestvr,onepopcorn/forestvr