Use stable sort for sorting coins (#235)

cointop/favorites.go

@@ -64,7 +64,7 @@ func (ct *Cointop) GetFavoritesSlice() []*Coin {
 		}
 	}
 
-	sort.Slice(sliced, func(i, j int) bool {
+	sort.SliceStable(sliced, func(i, j int) bool {
 		return sliced[i].MarketCap > sliced[j].MarketCap
 	})
 

cointop/portfolio.go

@@ -574,7 +574,7 @@ func (ct *Cointop) GetPortfolioSlice() []*Coin {
 		sliced = append(sliced, coin)
 	}
 
-	sort.Slice(sliced, func(i, j int) bool {
+	sort.SliceStable(sliced, func(i, j int) bool {
 		return sliced[i].Balance > sliced[j].Balance
 	})
 

cointop/sort.go

@@ -23,7 +23,7 @@ func (ct *Cointop) Sort(sortBy string, desc bool, list []*Coin, renderHeaders bo
 	if len(list) < 2 {
 		return
 	}
-	sort.Slice(list[:], func(i, j int) bool {
+	sort.SliceStable(list[:], func(i, j int) bool {
 		if ct.State.sortDesc {
 			i, j = j, i
 		}