* added clang system headers to data folder of Sourcetrail repo
* added clang system header search directory to detected directories on windows
* updated migration to add clang system header search directory on windows
* updated windows installer and portable package to include compiler headers
* updated linux package
* cleaned code of path detectors
* unrelated removal of unnecessary code in LicenseChecker and UpdateChecker
* replace path to local compiler headers with packaged ones in include path detection
* added app settings migration to replace local compiler header path with path to packaged headers
* renamed scripts
* moved install, uninstall, deleteConfig scripts to top-level
* fixed desktop file not recognized on installation, only on restart
* removed Eula accept from install script
* abort install and uninstall when not running as root
* revised README