Support for Multi-Channel Funnels API

[makkaq]

I've added support for the Multi-Channel Funnels Reporting API.

[nwellnhof]

This happens too late (_param is called after _uri) and causes a test failure.

[nwellnhof]

I agree with the approach to replace the realtime flag with a service string. But for a proper solution:

• Don't let Class::XSAccessor autogenerate the Request constructor.
• Add a manual implementation of the Request constructor that sets service if realtime is set.
• Remove the autogenerated realtime accessor in Request.
• Add a manual read/write realtime accessor that uses service internally for backward compatibility:

Something like the following (untested):

sub new {
    my ($class, %args) = @_;
    if (delete($args{realtime})) {
        $args{service} = 'realtime';
    }
    return bless(\%args, ref($class) || $class);
}

# For backward compatibility.
sub realtime {
    my $self = shift;
    if (@_) {
        my $val = shift;
        if ($val) {
            $self->{service} = 'realtime';
        }
        elsif (defined($self->{service}) && $self->{service} eq 'realtime') {
            $self->{service} = undef;
        }
        return $val;
    }
    else {
        return defined($self->{service}) && $self->{service} eq 'realtime';
    }
}

Then you can revert the change to _param.

Please fix the whitespace errors. It seems like you're using hard tabs or something.

Write a test for the MCF API. You can start from a copy of t/02-realtime.t.