Update site to fix links

- Fix #569
  - Windows links point to 4.0.4 release
  - Source release point to 4.0.4 github archives
  - OS X and Ubuntu point to previous 4.0.3 releases until new 4.0.4 ones are
    built
- Add downloads page for more detailed links to other builds etc.
- Update stylesheet to fix some download button formatting
- Update other links pointing at old repository urls

_layouts/home.html

@@ -5,13 +5,15 @@ layout: default
 <div class="home">
 <div class="container"><h1>{{ page.title | default: site.title }}</h1> 
     {%- if site.data.downloads -%}
-    <p>Download Latest Version: <strong>{{ site.data.downloads.version }}</strong></p>
-    <div class="downloads" style="display: flex; flex-wrap: wrap;">
-        {%- for download in site.data.downloads.files -%}
-        <a class="download" href="{{ download.link }}">
-            <svg class="svg-icon" viewBox="0 0 26 28"><use xlink:href="{{ '/assets/icons.svg' | relative_url }}#{{ download.icon }}"></use></svg><span>{{ download.name }}</span>
+    <p>Latest Downloads:</p>
+    <div class="downloads">
+        {%- for os in site.data.downloads.oses -%}
+        {%- for package in os.packages -%}
+        <a class="download" href="{{ package.link }}">
+            <svg class="svg-icon" viewBox="0 0 26 28"><use xlink:href="{{ '/assets/icons.svg' | relative_url }}#{{ os.icon }}"></use></svg><span>{{ os.name }} ({{ package.arch }})</span>
         </a>
         {%- endfor -%}
+        {%- endfor -%}
     </div>
     {%- endif -%}
 </div>