remove unused shell_utils, update upload_amo.sh to still work•••Even though upload_amo.sh scripts for extension signing is included, we're currently unable to use it because Firefox API keys needed for that require execution of nonfree JS and Jahoti's Mozoid tool is no longer working <https://hydrillabugs.koszko.org/issues/111>
v1.0-beta1
automatically pick up a free port to run the HTTP proxy on•••It is now possible to run multiple `make test` commands in parallel (e.g. testing abrowser and librewolf simultaneously after running `configure` for each of them in 2 different directories).