Add unit tests for buttons / relays; and a bunch of mocks :)

unittest/mgos_mock.h

@@ -5,6 +5,8 @@
  */
 
 #include "mgos.h"
+#include <time.h>
+#include "mongoose/mongoose.h"
 
 #define MGOS_APP "unittest"
 
@@ -38,6 +40,9 @@ typedef void (*timer_callback)(void *param);
 mgos_timer_id mgos_set_timer(int msecs, int flags, timer_callback cb, void *cb_arg);
 void mgos_clear_timer(mgos_timer_id id);
 
-float mg_time();
+double mgos_uptime();
+
+char *mgos_sys_ro_vars_get_mac_address();
+char *mgos_sys_ro_vars_get_arch();
 
 #endif // __MGOS_MOCK_H