The radare webserver is looking for http.root or http.homeroot which
wasn't included in the appimage, so the webserver failed to start.
Since sys/install.sh seems to just symlinks a lot of files in
/usr/share/radare2 cp -Lr the folder.
Additionally modify the http.root if an AppImage environment is detected.
* cleanup: get the include and lib path from r2
* clean up of the main project file
* check if r2 is available
* corrected r2 binary name m(
* qmake error if libr not found
Because the project won't build if r2 or the paths are not found emit
an error
* removed comments and unused variable
* Add 'make install' for AppImage
* Use 'make install' in travis build
