getopt, add --no-dirty-compressor and --no-jack-auto-connect command line arguments

This changes the `-dc` argument for `--no-dirty-compressor` and adds an additional argument `--no-jack-auto-connect` to disable JACK port autoconnection, to make it easier to use another compressor or more complex audio workflows with JACK.

Auto-connection is enabled by default, so running `./dirt` gets the normal behavior as always. I think it's good to auto-connect by default (regardless of the opinion of JACK users/developers), but better to have an option to disable for more advanced users.

I used *getopt.h* for command-line argument parsing, which is what most C GNU software use, based on [this example](http://www.gnu.org/software/libc/manual/html_node/Getopt-Long-Option-Example.html#Getopt-Long-Option-Example). This makes it easier to add new options in the future.