install.sh bug when ed is not present

[mechaniputer]

The installation script will fail if ed is not installed, but then if ed is then installed after such a failed attempt and the user tries to install again, it will fail indefinitely with no useful information until an uninstall is performed. This manifests on Debian which does not ship ed by default.

[sjrct]

tots my b, I remember getting frustrated with sed and then using ed instead. Really though, we should just be using sed, as it is in basically every standard install, which ed is pretty infrequent to be part of the base install.

so, the install script doesn't clean up after itself., which could be a problem generally. I think the fix for this is to just call uninstall here, at least in the case of a fresh install. When overwriting an existing install, maybe we can check updated timestamps, or offer to remove the install? Issue is, if we had a working halibot install and didn't break it, we probably don't want to remove the old install