fix(albert): Keep straps even when there's no SA

The width of the straps was calculated by multiplying with the `sa`
value.
As a result, when the user asks to draft a pattern without SA, the
straps drop off the pattern.

I've also change the way the width is calculated. It used to be based
on a percentage option that was then multiplied by SA.
While technically that follows the best practice of using percentages,
it won't scale with the model unless you multiply it with a measurement.

packages/albert/config/index.js

@@ -34,6 +34,6 @@ export default {
     chestDepth: { pct: 22, min: 15, max: 90 },
     bibLength: { pct: 75, min: 0, max: 90 },
     bibWidth: { pct: 100, min: 50, max: 125 },
-    strapWidth: { pct: 750, min: 100, max: 1500 }
+    strapWidth: { pct: 60, min: 20, max: 100 }
   }
 }

packages/albert/src/front.js

@@ -26,7 +26,7 @@ export default function (part) {
     (1 - options.backOpening)
   */
   let apronWidth = measurements.waist * (1 - options.backOpening)
-  let strapWidth = options.strapWidth * sa
+  let strapWidth = (measurements.hpsToWaistBack * options.strapWidth) / 8
   let hemWidth = 3 * sa
   let pocketSize = apronLength / 4
 

packages/albert/src/strap.js

@@ -31,9 +31,9 @@ export default function (part) {
     measurements.hpsToWaistBack -
     measurements.hpsToWaistBack * options.bibLength
 
+  let strapWidth = (measurements.hpsToWaistBack * options.strapWidth) / 8
   let strapLength =
     Math.sqrt(hSpan * hSpan + vSpan * vSpan) + measurements.chest * options.chestDepth
-  let strapWidth = options.strapWidth * sa
   /*
   console.log('chestWidth ' + chestWidth)
   console.log('backOpening ' + backOpening)