Removed SDL_bool in favor of plain bool

We require stdbool.h in the build environment, so we might as well use the plain bool type.

If your environment doesn't have stdbool.h, this simple replacement will suffice:
typedef signed char bool;

src/sensor/SDL_sensor.c

@@ -472,7 +472,7 @@ SDL_SensorID SDL_GetSensorID(SDL_Sensor *sensor)
 /*
  * Get the current state of this sensor
  */
-SDL_bool SDL_GetSensorData(SDL_Sensor *sensor, float *data, int num_values)
+bool SDL_GetSensorData(SDL_Sensor *sensor, float *data, int num_values)
 {
     SDL_LockSensors();
     {