[Dillo-dev][PATCH] use an alternative rcfile from command line

Hi to all, this little patch adds a command line option ( -R --rcfile) to specify an alternative rcfile from the command line. This is useful if you are calling dillo from scripts or other applications and you need to enable/disable some options for a particular task. The patch is against dillo 8.5. Please apply if you think it is ok to do so and the patch fits in the dillo philisophy. Ciao, Tito