Using Freeroute (autorouter) in Kicad 5
In Kicad 4, freeroute was included on the toolbar. In Kicad 5, they removed it. I disagree with this, but let's not debate. You can still use freeroute, though you must install it separately. And you need to export from Kicad the DSN (Spectra) file, then reimport the .ses file, as you would've before.
Download http://www.layouteditor.com/ (instructions from https://freerouting.org/freerouting/using-with-kicad). Extract and navigate to the bin folder, and you should find a freeRouting.jar
To run it:
cd layout/bin/ java -jar freeRouting.jar
Don't expect to get the traffic sign symbol anywhere in Kicad (as the freeroute webpage shows). Just export to a spectra file then import that file into Freeroute.
Editing Files Directly
Kicad is programmed in lisp, and the data files are lists.
Make a backup of your file (e.g. kicad_pcb) then change resistor label to be hidden (in text editor) change
(fp_text reference R20 (at 0 -1.43) (layer F.SilkS)
(fp_text reference R20 (at 0 -1.43) (layer F.SilkS) hide