Added c-compatible gaurds to events.h

Allows events.h to be included from C files to access the C api.

note: This does not introduce the C api into the namespace.
      The C api was previously dragged in indirectly from EventQueue.h.

Author: geky

EventQueue.cpp

@@ -1,6 +1,5 @@
 #include "EventQueue.h"
 
-#include "events-c/events.h"
 #include "events.h"
 #include "mbed.h"
 

events.h

@@ -16,9 +16,18 @@
 #ifndef EVENTS_CPP_H
 #define EVENTS_CPP_H
 
+
+#include "events-c/events.h"
+
+
+#ifdef __cplusplus
+
 #include "EventQueue.h"
 #include "EventLoop.h"
 
 using namespace events;
 
 #endif
+
+
+#endif