refactor sources to be more flexible

owrx/source/rtl_sdr.py

@@ -2,15 +2,6 @@ from .connector import ConnectorSource
 
 
 class RtlSdrSource(ConnectorSource):
-    def getCommand(self):
-        cmd = (
-                "rtl_connector -p {port} -c {controlPort}".format(port=self.port, controlPort=self.controlPort)
-                + " -s {samp_rate} -f {tuner_freq} -g {rf_gain} -P {ppm}"
-        )
-        if "device" in self.rtlProps and self.rtlProps["device"] is not None:
-            cmd += ' -d "{device}"'
-        if self.rtlProps["iqswap"]:
-            cmd += " -i"
-        if self.rtlProps["rtltcp_compat"]:
-            cmd += " -r"
-        return cmd
+    def __init__(self, id, props, port):
+        super().__init__(id, props, port)
+        self.getCommandMapper().setBase("rtl_connector")