SITL: correct typos in comments

libraries/SITL/SIM_Frame.h

@@ -98,7 +98,7 @@ private:
         // battery capacity in Ah. Use zero for unlimited
         float battCapacityAh = 0.0;
 
-        // CTUN.ThO at bover at refAlt
+        // CTUN.ThO at hover at refAlt
         float hoverThrOut = 0.39;
 
         // MOT_THST_EXPO
@@ -121,7 +121,7 @@ private:
         float slew_max = 150;
 
         // rotor disc area in m**2 for 4 x 0.35m dia rotors
-        // Note that coaxial rotors count as one rotor only when cauclating effective disc area
+        // Note that coaxial rotors count as one rotor only when calculating effective disc area
         float disc_area = 0.385;
 
         // momentum drag coefficient

libraries/SITL/SITL.h

@@ -174,7 +174,7 @@ public:
     AP_Int8 mag_fail[HAL_COMPASS_MAX_SENSORS];   // fail magnetometer, 1 for no data, 2 for freeze
     AP_Float servo_speed; // servo speed in seconds
 
-    AP_Float sonar_glitch;// probablility between 0-1 that any given sonar sample will read as max distance
+    AP_Float sonar_glitch;// probability between 0-1 that any given sonar sample will read as max distance
     AP_Float sonar_noise; // in metres
     AP_Float sonar_scale; // meters per volt
 
@@ -215,7 +215,7 @@ public:
     AP_Int8  terrain_enable; // enable using terrain for height
     AP_Int16 pin_mask; // for GPIO emulation
     AP_Float speedup; // simulation speedup
-    AP_Int8  odom_enable; // enable visual odomotry data
+    AP_Int8  odom_enable; // enable visual odometry data
     AP_Int8  telem_baudlimit_enable; // enable baudrate limiting on links
     AP_Float flow_noise; // optical flow measurement noise (rad/sec)
     AP_Int8  baro_count; // number of simulated baros to create