util.c: floating point timers for game loop

src/context.h

@@ -39,6 +39,7 @@ typedef struct context {
     int64_t frame_accumulator;
     int64_t delta_averager_residual; 
     int64_t time_averager[4];
+    int64_t delta_time; /* preserves real time frame delta with no manipilation */
     uint64_t tick_count;
     uint64_t step_count;