macOS compilation steps are not working

[nbigaouette]

As mentioned in #345, I'm attempting to compile panopticon on macOS High Sierra but unfortunately it's failing.

Here's what is not working:

1. brew linkapps qt --> linkapps was deprecated and is not available anymore. Is it really necessary?
2. Creating symbolic links fails due to permissions:

ln -s /usr/local/Cellar/qt/$HOMEBREW_QT5_VERSION/mkspecs /usr/local/mkspecs
ln: /usr/local/mkspecs: Permission denied

ls -ldh /usr/local/
drwxr-xr-x  15 root  wheel   480B  3 Nov 20:27 /usr/local/

I've created the links as root using sudo...
3. Running fails since panopticon-qt is not a package:

cargo run -p panopticon-qt --release

The package panopticon should probably be used instead?