rtl_tcp: add get_devices member which returns a default device

lib/rtl_tcp/rtl_tcp_source_c.cc

@@ -132,7 +132,18 @@ gr_basic_block_sptr rtl_tcp_source_c::self()
 
 std::string rtl_tcp_source_c::name()
 {
-  return "RTL TCP Client Source";
+  return "RTL TCP Client";
+}
+
+std::vector<std::string> rtl_tcp_source_c::get_devices()
+{
+  std::vector<std::string> devices;
+
+  std::string args = "rtl_tcp=localhost:1234";
+  args += ",label='RTL-SDR Spectrum Server'";
+  devices.push_back( args );
+
+  return devices;
 }
 
 size_t rtl_tcp_source_c::get_num_channels( void )

lib/rtl_tcp/rtl_tcp_source_c.h

@@ -48,6 +48,8 @@ public:
 
   std::string name();
 
+  static std::vector< std::string > get_devices();
+
   size_t get_num_channels( void );
 
   osmosdr::meta_range_t get_sample_rates( void );