AP_HAL_Empty: move implementations of functions to header

Makes it much clearer what's implemented and what's dangling

libraries/AP_HAL_Empty/Scheduler.cpp

@@ -1,36 +0,0 @@
-
-#include "Scheduler.h"
-
-#include <stdarg.h>
-
-using namespace Empty;
-
-extern const AP_HAL::HAL& hal;
-
-Scheduler::Scheduler()
-{}
-
-void Scheduler::init()
-{}
-
-void Scheduler::delay(uint16_t ms)
-{}
-
-void Scheduler::delay_microseconds(uint16_t us)
-{}
-
-void Scheduler::register_timer_process(AP_HAL::MemberProc k)
-{}
-
-void Scheduler::register_io_process(AP_HAL::MemberProc k)
-{}
-
-void Scheduler::register_timer_failsafe(AP_HAL::Proc, uint32_t period_us)
-{}
-
-void Scheduler::set_system_initialized()
-{}
-
-void Scheduler::reboot(bool hold_in_bootloader) {
-    for(;;);
-}

libraries/AP_HAL_Empty/Scheduler.h

@@ -4,18 +4,18 @@
 
 class Empty::Scheduler : public AP_HAL::Scheduler {
 public:
-    Scheduler();
-    void     init() override;
-    void     delay(uint16_t ms) override;
-    void     delay_microseconds(uint16_t us) override;
-    void     register_timer_process(AP_HAL::MemberProc) override;
-    void     register_io_process(AP_HAL::MemberProc) override;
+    Scheduler() {}
+    void     init() override {}
+    void     delay(uint16_t ms) override {}
+    void     delay_microseconds(uint16_t us) override {}
+    void     register_timer_process(AP_HAL::MemberProc) override {}
+    void     register_io_process(AP_HAL::MemberProc) override {}
 
-    void     register_timer_failsafe(AP_HAL::Proc, uint32_t period_us) override;
+    void     register_timer_failsafe(AP_HAL::Proc, uint32_t period_us) override {}
 
-    void     set_system_initialized() override;
+    void     set_system_initialized() override {}
     bool     is_system_initialized() override { return true; }
 
-    void     reboot(bool hold_in_bootloader) override;
+    void     reboot(bool hold_in_bootloader) override { for (;;); }
 
 };