Throw on failure to connect to server

I'm not quite sure, but wouldn't it be better to fail with an exception when not being able to connect to the server, instead of just logging:

DaemonMode.jl/src/DaemonMode.jl

Line 256 in 24930ea

println(stderr, "Error, cannot connect with server. Is it running?")

My current use case is a simple bash script which falls back to using Julia without the daemonmode if not installed or running. I would then need to parse the output in stderr instead of using the return value.

I have just update the code to return the code when there is a simple error (as it cannot connect to the server, or the file is not found). It is in the current master version.
I want to return also when any exception is returned for next version, but it could take more time, because I have to change the communications.

The last version is better for scripting. It returns the error code if there is an error in the case of not connection or Exception.