jekyll: move jekyll back to root, but simpler setup, exclude via _config.yml

app: bundle jekyll docs into app, add 'yarn run docs' to build
ui: add back/forward arrows for app only, adjust responsiveness for app, add IS_APP flag injected via preload
ui: add animated logo, friendly message on empty replay frame
app: improve serve logic:
- serve static files from static root
- serve replay from http localhost instead to avoid proxying https for remote requests
- serve local lookup from http prefix also
- catch any fallthrough from replay as 404
- add timestamp to response channels to ensure uniqness

_sass/custom/custom.scss

@@ -0,0 +1,37 @@
+$rwp-green: #55be6f;
+$rwp-yellow: #f5c71a;
+$rwp-blue: #4876ff;
+//$link-color: #27a0ff;
+$link-color: #384ea2;
+
+//$content-width: 960px;
+$nav-width-md: $nav-width;
+
+.side-bar {
+  @include mq(md) {
+    //max-width: calc(0.5rem + #{$nav-width});
+    max-width: $nav-width;
+  }
+}
+
+.site-title {
+  padding-right: 1.5rem !important;
+}
+
+.rwp-logo-font {
+  font-variant-caps: all-small-caps;
+  font-size: 20px;
+  font-weight: bold;
+}
+
+.rwp-green {
+  color: $rwp-green;
+}
+
+.rwp-yellow {
+  color: $rwp-yellow;
+}
+
+.rwp-blue {
+  color: $rwp-blue;
+}