Add a debug mode to have more logs,...

When using the javascript API of the installer framework it is pretty hard to debug has there is only logs when the installation succeed (the log file is in the installation folder).

IMO the console.log function should print in the console when we launch the installer from a terminal (cmd for windows or bash for linux,...). In this case even the uninstaller will be able to report some logs.

Also the framework doesn't report enough when there is errors in scripts for build the GUI,...

If I miss a way to do that, maybe this is only a documentation issue.