Major wip refactor

Allow running without gui
Remove serialPortMultiplexer broadcast use
Add TcpServer and TcpClient
Introduce the concept of an item source

src/programmode.h

@@ -0,0 +1,13 @@
+#ifndef PROGRAMMODE_H
+#define PROGRAMMODE_H
+
+typedef enum
+{
+	PROGRAM_MODE_PRIMARY = 0,
+	PROGRAM_MODE_HEADLESS_PRIMARY,
+	PROGRAM_MODE_UI_ONLY
+} program_mode_t;
+
+extern program_mode_t programMode;
+
+#endif // PROGRAMMODE_H