tig appimage guide

tig-appimage-guide

* Create tig appimage
** get tig src file zip or using git into ~/public/tig
** compile
   - make
   - fix the dependencies
** generate the appimage file
   - download linuxdeploy appimage and make it executable
   - write the right tig.desktop and log tig.png, the logo can be empty tig.svg file
   - ./linuxdeploy.appimage -e ./src/tig -i ./tig.png -d ./tig.desktop --appdir AppDir --output appimage
	 + NOTE: in docker, you may unable to run appimage directly
	 + if compile from git src, linuxdeploy will use git hash id for version in output appimage name
	   * `export VERSION=ver_num;` first for this situation
	 + if linuxdeploy.appimage is unable to be run directly in some systems, use this:
	   * check https://github.com/AppImage/AppImageKit/wiki/FUSE, if it cannot be fixed, try the following step:
	   * ./linuxdeploy-x86_64.AppImage --appimage-extract-and-run -e ./src/tig -i ./tig.png -d ./tig.desktop --appdir AppDir --output appimage
   - you will get tig.xx.appimage file