Fixed .linux.spec file to build application folder with about.txt file and other updated settings.
Enhanced with a 1st and 2nd attempt at setting self.appdir variable with working folder path.
Variances occur between platforms and launch methods; if 1st technique returns blank or root as launch path, the 2nd technique is used. This covers all witnessed variances.
This fix allows it to run from both source (enabling faster development cycles) as well as from the built application folder (nice user experience).