* Added support for SUSE and derivatives for command-not-found plugin

* Updated command-not-found documentation to list support for SUSE and derivatives

`pk-command-not-found` doesn't accept `--` as an argument. This is what happens when `--` is the first argument:

```
$  gem
zsh: --: command not found...
```

By sourcing brew files directly we can achieve a very high speed up.
This will not work if the user installed homebrew in a different
location than by default.

* use https everywhere

* use https links on the files that are left

Also, removed some broken links and updated redirections.