custom configuration file option



If we have multiple access logs with different formats we cannot use just one config.
With a new commandline option we could define a new "goaccessrc" config file.

eg:

    goaccess -p /home/me/goaccessrc1 -f access_format1.log
    goaccess -p /home/me/goaccessrc2 -f access_format2.log

this diff is related to [feature request 9](https://github.com/allinurl/goaccess/issues/9).

best,