warnings: Fix a bunch of warnings

This is in prep to turn on more warnings.

  - Stop using libusb_set_debug, according to the deprecation warning for
    libusb.
  - Return correctly in G13_Manager::run
  - Fix the ostream logging helper to return an ostream instead of just
    returning whatever the last expression was.

src/g13.cc

@@ -747,7 +747,7 @@ int G13_Manager::run() {
 		return 1;
 	}
 
-	libusb_set_debug(ctx, 3);
+	libusb_set_option(ctx, LIBUSB_OPTION_LOG_LEVEL, 3);
 	cnt = libusb_get_device_list(ctx, &devs);
 	if (cnt < 0) {
 		G13_LOG( error, "Error while getting device list" );
@@ -788,6 +788,8 @@ int G13_Manager::run() {
 			}
 	} while (running);
 	cleanup();
+
+    return 0;
 }
 } // namespace G13
 

src/helper.h

@@ -178,6 +178,7 @@ STREAM_T &operator <<( STREAM_T &o, const _map_keys_out<MAP_T> &_mko ) {
 			o << _mko.sep << i->first;
 		}
 	}
+    return o;
 };
 
 template <class MAP_T>