Run command line arguments in active instance instead of silently throw them away.

[Gero.Bare]

Run command line arguments in active instance instead of silently throw them away if an instance of an app is already running.

Example:

You have a Scratch instance, if you open you terminal and write:

$ scratch-text-editor ~/my_file.txt

It should open a new tab in a running instance of scratch, instead of simply exit.
In the case of scratch, in only needs to process the command_line method.