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

_data/downloads.yml

@@ -1,15 +1,27 @@
-version: 4.0.3
-files:
-  - name: Windows (x64)
-    link: https://github.com/arsenetar/dupeguru/releases/download/4.0.3-InstallFix/dupeGuru_win64_4.0.3.exe
-    icon: windows
-  - name: Linux (ppa)
-    link: https://launchpad.net/~hsoft/+archive/ppa/+packages
+oses:
+  - name: Windows
+    icon: windows 
+    packages: 
+      - arch: x64
+        link: https://github.com/arsenetar/dupeguru/releases/download/4.0.4/dupeGuru_win64_4.0.4.exe
+      - arch: x32
+        link: https://github.com/arsenetar/dupeguru/releases/download/4.0.4/dupeGuru_win32_4.0.4.exe
+  - name: Ubuntu
     icon: linux
+    packages:
+      - arch: x32, x64
+        link: https://launchpad.net/~hsoft/+archive/ppa/+packages
   - name: OS X
-    link: https://download.hardcoded.net/dupeguru_osx_4_0_3.dmg
+    icon: apple
+    packages:
+      - arch: "10.10+"
+        link: https://github.com/arsenetar/dupeguru/releases/download/4.0.3/dupeguru_osx_4_0_3.dmg
     icon: apple
   - name: Source
-    link: https://github.com/arsenetar/dupeguru/archive/4.0.3-InstallFix.tar.gz
     icon: github
+    packages:
+      - arch: zip
+        link: https://github.com/arsenetar/dupeguru/archive/4.0.4.zip
+      - arch: tar.gz
+        link: https://github.com/arsenetar/dupeguru/archive/4.0.4.tar.gz
     

_data/externallinks.yml

@@ -1,4 +1,4 @@
 - title: Help
   url: /help/en/
 - title: Github
-  url: https://github.com/hsoft/dupeguru/
+  url: https://github.com/arsenetar/dupeguru/