Add teardown function for the event.c module

Also move the `job_teardown` call from os_unix.c to the event module

src/os/event.c

@@ -41,6 +41,11 @@ void event_init()
   uv_prepare_init(uv_default_loop(), &timer_prepare);
 }
 
+void event_teardown()
+{
+  job_teardown();
+}
+
 // Wait for some event
 bool event_poll(int32_t ms)
 {

src/os/event.h

@@ -8,6 +8,7 @@
 #include "os/job_defs.h"
 
 void event_init(void);
+void event_teardown(void);
 bool event_poll(int32_t ms);
 bool event_is_pending(void);
 void event_push(Event event);

src/os_unix.c

@@ -581,7 +581,7 @@ void mch_exit(int r)
 {
   exiting = TRUE;
 
-  job_teardown();
+  event_teardown();
 
   {
     settmode(TMODE_COOK);