add clear method

satrs/src/ccsds/scheduler.rs

@@ -282,6 +282,11 @@ pub mod alloc_mod {
         > {
             self.tc_map.range(..=self.current_time)
         }
+
+        /// Completely clear the scheduler.
+        pub fn clear(&mut self) {
+            self.tc_map.clear();
+        }
     }
 }