Add processing of .pth files from "app_packages".#63

timrid wants to merge 1 commit intobeeware:mainbeeware/briefcase-windows-app-template:mainfrom

timrid:bugfix/pth-file-processing-in-app-packagestimrid/briefcase-windows-app-template:bugfix/pth-file-processing-in-app-packagesCopy head branch name to clipboard