Initial block difficulty adjustment + difficulty adjustment scenario modification (#1217)

* Handle SIGINT and SIGTERM (#1180)

* Handle SIGINT and SIGTERM

* pin croaring to version 0.3.2 until we get the clang conflict sorted out (#1183)

* document proposals for - (#1190)

* conditional timelocked outputs, and
* conditional relative timelocked outputs

* problem with validation on rewind

* update difficulty scenarios to display much more data

* correct average sum output

* update pre-genesis block padding to just use previous block's data

core/src/consensus.rs

@@ -215,7 +215,7 @@ where
 	let earliest_ts = window_earliest[MEDIAN_TIME_INDEX as usize];
 
 	// Obtain the median window for the latest time period
-	// i.e. the last  MEDIAN_TIME_WINDOW elements
+	// i.e. the last MEDIAN_TIME_WINDOW elements
 	let mut window_latest: Vec<u64> = diff_data
 		.iter()
 		.skip(DIFFICULTY_ADJUST_WINDOW as usize)

core/src/global.rs

@@ -249,7 +249,6 @@ where
 				live_intervals[i].0 = live_intervals[i].0 - live_intervals[i - 1].0;
 			}
 		}
-		//
 		// Remove genesis "interval"
 		if live_intervals.len() > 1 {
 			live_intervals.remove(0);
@@ -259,14 +258,11 @@ where
 		}
 		let mut interval_index = live_intervals.len() - 1;
 		let mut last_ts = last_n.first().as_ref().unwrap().as_ref().unwrap().0;
-		// fill in simulated blocks, repeating whatever pattern we've obtained from
-		// real data
-		// if we have, say, 15 blocks so far with intervals of I1..I15, then
-		// the 71-15=56 pre genesis blocks will have
-		// intervals/difficulties I1..I15 I1..I15 I1..I15 I1..I11
+		let last_diff = live_intervals[live_intervals.len()-1].1;
+		// fill in simulated blocks with values from the previous real block
+
 		for _ in 0..block_count_difference {
-			last_ts = last_ts.saturating_sub(live_intervals[interval_index].0);
-			let last_diff = &live_intervals[interval_index].1;
+			last_ts = last_ts.saturating_sub(live_intervals[live_intervals.len()-1].0);
 			last_n.insert(0, Ok((last_ts, last_diff.clone())));
 			interval_index = match interval_index {
 				0 => live_intervals.len() - 1,