Fix for incorrect division in fee estimation.

refs #65

backend/src/api/fee-api.ts

@@ -30,7 +30,7 @@ class FeeApi {
   }
 
   private optimizeMedianFee(pBlock: MempoolBlock, previousFee?: number): number {
-    const useFee = previousFee ? (pBlock.medianFee + previousFee / 2) : pBlock.medianFee;
+    const useFee = previousFee ? (pBlock.medianFee + previousFee) / 2 : pBlock.medianFee;
     if (pBlock.blockVSize <= 500000) {
       return this.defaultFee;
     }