treewide: use more HTTPS URLs

Uses the HTTPS url for cases where the existing URL has a permanent
redirect. For each domain, at least one fixed derivation URL was
downloaded to test the domain is properly serving downloads.

Also fixes jbake source URL, which was broken.

pkgs/development/python-modules/jsonref/default.nix

@@ -19,7 +19,7 @@ buildPythonPackage rec {
 
   meta = with stdenv.lib; {
     description = "An implementation of JSON Reference for Python";
-    homepage    = "http://github.com/gazpachoking/jsonref";
+    homepage    = "https://github.com/gazpachoking/jsonref";
     license     = licenses.mit;
     maintainers = with maintainers; [ nand0p ];
     platforms   = platforms.all;