Upgrade docs to DocLog 2.0. Includes a test learning page

doclog.config.pl

@@ -0,0 +1,11 @@
+project_name("Scryer Prolog").
+readme_file("INDEX.dj").
+source_lib_folder("src/lib").
+websource("https://github.com/mthom/scryer-prolog/tree/master/src/lib").
+omit(["ops_and_meta_predicates.pl", "tabling"]).
+learn_pages_source_folder("learn").
+learn_pages_categories(["First steps"]).
+learn_pages([
+		   page("Test page", "First steps", "test-page.dj")
+]).
+copy_file("logo/scryer.png", "scryer.png").