Job tweaks (#1253)

* In status reports, use SD tag for macro progress

This makes various UI things work right

* Use Job leader for command output channel when appropriate

This fixes some crashes that could occur when messages were being
sent to file channels.

FluidNC/src/Machine/Macros.cpp

@@ -131,7 +131,7 @@ Error MacroChannel::pollLine(char* line) {
             float percent_complete = (float)_position * 100.0f / _macro->get().length();
 
             std::ostringstream s;
-            s << name() << ":" << std::fixed << std::setprecision(2) << percent_complete;
+            s << "SD:" << std::fixed << std::setprecision(2) << percent_complete << "," << name();
             _progress = s.str();
         }
             return Error::Ok;

FluidNC/src/Protocol.cpp

@@ -281,7 +281,8 @@ void protocol_main_loop() {
                 report_echo_line_received(activeLine, allChannels);
             }
 
-            Error status_code = execute_line(activeLine, *activeChannel, WebUI::AuthenticationLevel::LEVEL_GUEST);
+            Channel* out_channel = Job::leader ? Job::leader : activeChannel;
+            Error    status_code = execute_line(activeLine, *out_channel, WebUI::AuthenticationLevel::LEVEL_GUEST);
 
             // Tell the channel that the line has been processed.
             // If the line was aborted, the channel could be invalid