Add detection of firewall blocking non-port 80 connections

[ikreymer]

Netcapsule makes connection to a randomly assigned port to connect to the browser.
Unfortunately, it appears that some firewall software is blocking connections to ports other than 80, and so the system is stuck at "Initializing Browser"

Attempt to detect this and notify the user that the connection is blocked and they can't use oldweb.today (until there is a workaround)