AC_Sprayer: append f to floating point constants

Reduces some compiler warnings

libraries/AC_Sprayer/AC_Sprayer.cpp

@@ -58,7 +58,7 @@ AC_Sprayer::AC_Sprayer(const AP_InertialNav* inav) :
     AP_Param::setup_object_defaults(this, var_info);
 
     // check for silly parameter values
-    if (_pump_pct_1ms < 0 || _pump_pct_1ms > 100) {
+    if (_pump_pct_1ms < 0.0f || _pump_pct_1ms > 100.0f) {
         _pump_pct_1ms.set_and_save(AC_SPRAYER_DEFAULT_PUMP_RATE);
     }
     if (_spinner_pwm < 0) {
@@ -151,7 +151,7 @@ AC_Sprayer::update()
 
     // if testing pump output speed as if travelling at 1m/s
     if (_flags.testing) {
-        ground_speed = 100;
+        ground_speed = 100.0f;
     }
 
     // if spraying or testing update the pump servo position

libraries/AC_Sprayer/AC_Sprayer.h

@@ -27,7 +27,7 @@
 #include <RC_Channel.h>
 #include <AP_InertialNav.h>     // Inertial Navigation library
 
-#define AC_SPRAYER_DEFAULT_PUMP_RATE        10       // default quantity of spray per meter travelled
+#define AC_SPRAYER_DEFAULT_PUMP_RATE        10.0f   // default quantity of spray per meter travelled
 #define AC_SPRAYER_DEFAULT_PUMP_MIN         0       // default minimum pump speed expressed as a percentage from 0 to 100
 #define AC_SPRAYER_DEFAULT_SPINNER_PWM      1300    // default speed of spinner (higher means spray is throw further horizontally
 #define AC_SPRAYER_DEFAULT_SPEED_MIN        100     // we must be travelling at least 1m/s to begin spraying