Mitigate theoretical censor attack and some script clean-up

This PR includes:
1) A change to bridge torrc configuration so that bridges bind their OR ports on a non-standard high port. The attack I'm trying to mitigate is a censor scanning the internet for Tor nodes on port 443/9001 (by far the most common ones in documentation/the Tor directory) and deducing/blocking the bridges.
2) Minor installer.sh clean-up

cc @diogomonica