Fix #114: use presetColors(t.id) for theme card swatches

t.colors was removed by #113; rendering threw on first iteration and
the theme grid rendered empty. Use the colors returned by
presetColors(t.id) instead. Verified in headless chromium: 5
theme-card elements render on /settings.

internal/web/templates/settings.html

@@ -44,7 +44,7 @@
     btn.className = 'theme-card';
     btn.setAttribute('aria-pressed', current === t.id ? 'true' : 'false');
     btn.innerHTML = '<strong>' + t.name + '</strong>' +
-      '<span class="swatches">' + t.colors.map(function (c) {
+      '<span class="swatches">' + colors.map(function (c) {
         return '<span class="swatch" style="background:' + c + '"></span>';
       }).join('') + '</span>';
     btn.addEventListener('click', function () {