Add extern "C" modifiers to main public header files for mixing C/C++. Minor modifications to pull request from @bacek.

kernel/atomtimer.h

@@ -30,6 +30,10 @@
 #ifndef __ATOM_TIMER_H
 #define __ATOM_TIMER_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "atomport.h"
 
 
@@ -58,4 +62,8 @@ extern uint8_t atomTimerDelay (uint32_t ticks);
 extern uint32_t atomTimeGet (void);
 extern void atomTimeSet (uint32_t new_time);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __ATOM_TIMER_H */