support auto-start and configuration file

[Marcos Alano]

The application autocutsel has a strong similarity with unclutter package because both are small X tools which should be executed before user session. My suggestion is create a configuration file at /etc/default similar to the file present on unclutter where you can enable or disable auto-start and set command line options. The other file created should be /etc/X11/Xsession.d/90autocutsel so the application can start automatically.