README.md: fix link to README on github, and update comments for commercial support.

info.xml

@@ -15,10 +15,10 @@
     <ver>4.4</ver>
     <ver>4.5</ver>
   </compatibility>
-  <comments>See the README.md file.</comments>
+  <comments>Commercial support available from https://www.SymbioTIC.coop</comments>
   <urls>
     <url desc="Main Extension Page">https://github.com/mlutfy/ca.bidon.civiexportexcel</url>
-    <url desc="Documentation">https://github.com/mlutfy/ca.bidon.civiexportexcel/blob/master/README.txt</url>
+    <url desc="Documentation">https://github.com/mlutfy/ca.bidon.civiexportexcel/blob/master/README.md</url>
     <url desc="Support">http://forum.civicrm.org/index.php/board,57.0.html</url>
     <url desc="Licensing">http://civicrm.org/licensing</url>
   </urls>