Add reference to DG in homepage footer. Spacing in top links.

index.html

@@ -26,7 +26,7 @@
 
   <div class="col-sm-6 col-md-3">
     <h3>Get started</h3>
-    <ul>
+    <ul class="mb-2">
       <li><a href="https://www.youtube.com/watch?v=x1LFbDQhbso">Google Tech Talk</a></li>
       <li>
         <a href="http://cloud.grammaticalframework.org/">
@@ -46,7 +46,7 @@
   <div class="col-sm-6 col-md-3">
     <h3>Learn more</h3>
 
-    <ul>
+    <ul class="mb-2">
       <li><a href="gf-book">The GF Book</a></li>
       <li><a href="doc/gf-refman.html">Reference Manual</a></li>
       <li><a href="doc/gf-shell-reference.html">Shell Reference</a></li>
@@ -61,7 +61,7 @@
 
   <div class="col-sm-6 col-md-3">
     <h3>Develop</h3>
-    <ul>
+    <ul class="mb-2">
       <li><a href="doc/gf-developers.html">Developers Guide</a></li>
       <!-- <li><a href="/~hallgren/gf-experiment/browse/">Browse Source Code</a></li> -->
       <li><a href="http://hackage.haskell.org/package/gf/docs/PGF.html">PGF library API (Haskell runtime)</a></li>
@@ -75,7 +75,7 @@
 
   <div class="col-sm-6 col-md-3">
     <h3>Contribute</h3>
-    <ul>
+    <ul class="mb-2">
       <li><a href="http://groups.google.com/group/gf-dev">Mailing List</a></li>
       <li><a href="https://github.com/GrammaticalFramework/gf-core/issues">Issue Tracker</a></li>
       <li><a href="doc/gf-people.html">Authors</a></li>
@@ -372,9 +372,12 @@ least one, it may help you to get a first idea of what GF is.
 
 </div><!-- .container -->
 
-<footer class="bg-light mt-5 py-5">
-  <div class="container mb-5">
-    <div class="row">
+<footer class="bg-light mt-5 py-4">
+  <div class="container mb-3">
+    <div class="text-center text-muted">
+      <img style="height:50px; filter: opacity(.5) grayscale(1);" class="mb-3" src="doc/Logos/gf0.svg" alt="GF Logo"><br>
+      Grammatical Framework is free and open source,<br>
+      with some support from <a href="https://www.digitalgrammars.com/">Digital Grammars AB</a>.
     <div>
   <div>
 </footer>