add shadow docs, add ztop limit to pocket and trace

src/geo/base.js

@@ -160,6 +160,12 @@ function inRange(value, min, max) {
 }
 
 function round(v, zeros) {
+    if (typeof v === 'object') {
+        for (let [key,val] of Object.entries(v)) {
+            v[key] = round(val);
+        }
+        return v;
+    }
     const prec = zeros !== undefined ? zeros : round_decimal_precision;
     if (prec === 0) return v | 0;
     let pow = Math.pow(10, prec);