DCABuilder slippage parameter fix

src/blockchain/orderlib.js

@@ -1,5 +1,6 @@
 import {uint32max, uint64max} from "@/misc.js";
 import {encodeIEE754} from "@/common.js";
+import {DEFAULT_SLIPPAGE} from "@/orderbuild.js";
 
 export const MAX_FRACTION = 65535;
 export const NO_CONDITIONAL_ORDER = uint64max;
@@ -86,6 +87,10 @@ export function newTranche({
     if( marketOrder ) {
         if (minIntercept !== 0 || minSlope !== 0 || maxIntercept !== 0 || maxSlope !== 0)
             console.warn('Ignoring line information in a market order')
+        if (slippage === 0) {
+            console.warn(`setting market order slippage to ${DEFAULT_SLIPPAGE}`)
+            slippage = DEFAULT_SLIPPAGE
+        }
         minIntercept = encodeIEE754(slippage)  // this is the slippage field for market orders
         minSlope = 0
         maxIntercept = 0