creating an AppImage to distribute Linux binaries

Some notes of my AppImage creation process.

1. First tried creating manually, using
   https://github.com/AppImage/docs.appimage.org/blob/master/source/packaging-guide/manual.rst and the AppRunx86-64 from https://github.com/AppImage/AppImageKit/releases
2. Found and copied the libs it uses by doing the following to copy all shared libraries -https://www.commandlinefu.com/commands/view/10238/copy-all-shared-libraries-for-a-binary-to-directory
   ldd file | grep "=> /" | awk '{print $3}' | xargs -I '{}' cp -v '{}' /destination
3. Need to use the environment variable $OWD (Original Working Directory) to get files from the OWD, like our ini file. This code snippet was a good template, https://stackoverflow.com/questions/40306012/c-using-environment-variables-for-paths
       char* pPath;
       pPath = getenv("PATH");
       if (pPath)
         std::cout << "Path =" << pPath << std::endl;
       return 0;
4. Many libs copied with the manual method had to be excluded using the excludelist at
   https://github.com/AppImage/pkg2appimage/blob/master/excludelist
5. Still did not work on newer distros. In this thread, probono recommended using trusty on TravisCI for building, and linuxdeployqt instead of manual creation of AppDir. Did that, and it worked. Far fewer libs are bundled by linuxdeployqt. Lists of the two bundles are available at this issue thread.
6. The download link from transfer.sh can be seen if the entire log is downloaded from TravisCI.
7. The travis yml file gives the outline of the build and bundling process.