Report as 100% synced if the latest block is within the last 30 mins

This should hopefully reduce confusion due to APIs reporting 99% synced even though up to date. The systray should never show this since it already treats blocks in the last 30 mins as synced.

src/main/java/org/qortal/api/model/NodeStatus.java

@@ -24,7 +24,7 @@ public class NodeStatus {
 		this.isMintingPossible = Controller.getInstance().isMintingPossible();
 
 		this.syncPercent = Synchronizer.getInstance().getSyncPercent();
-		this.isSynchronizing = this.syncPercent != null;
+		this.isSynchronizing = Synchronizer.getInstance().isSynchronizing();
 
 		this.numberOfConnections = Network.getInstance().getImmutableHandshakedPeers().size();
 

src/main/java/org/qortal/controller/Synchronizer.java

@@ -173,6 +173,12 @@ public class Synchronizer extends Thread {
 
 	public Integer getSyncPercent() {
 		synchronized (this.syncLock) {
+			// Report as 100% synced if the latest block is within the last 30 mins
+			final Long minLatestBlockTimestamp = NTP.getTime() - (30 * 60 * 1000L);
+			if (Controller.getInstance().isUpToDate(minLatestBlockTimestamp)) {
+				return 100;
+			}
+
 			return this.isSynchronizing ? this.syncPercent : null;
 		}
 	}