Rewrite to use 'dns-sd' directly instead of dependency library due to difficulty installing dependency on MacOS

[Snapperfish]

Using the ruby script was problematic on MacOS Sierra (and presumably later versions).

1. Added instructions to create the required scripts without running the ruby script.
2. Rewrote script to use dns-sd system command directly instead of ruby dependency.

[MrPaulAR]

Used yours for one less dependency. Thanks!

[ppbpp]

thank you! worked like a charm