Add parameter serviceUrl

[MonsieurV]

I added a parameter serviceUrl, for letting configure the service base URL.
This is useful when you're developing or when you host you're on version of the compiler services.

The default behavior is still the same.

[kpym]

@MonsieurV thanks for your contribution. Do you accept to rename the switch from serviceUrl to simply url because there are no other urls. My proposal is :

	pflag.String("url", "", "The base url for the service. If empty, the default URL is used.")

[kpym]

@MonsieurV Two more things.

1. I prefere to not commit my .gitignore (I have one also) in this repo.
2. I prefer to keep my .goreleaser.yml as is, including the archives section you commented on.

Thanks in advance.

[MonsieurV]

@kpym ok, that's done. I've squashed so the history is kept clean.

[kpym]

@MonsieurV Thanks !