Restructure index

Move the API to the end, recipes all grouped together up-front (with
remote GPIO setup just before the remote GPIO recipes). Tweak some
headings so everything looks a little more consistent in the (now
shorter) ToC.

Also added module index tags.

docs/index.rst

@@ -7,8 +7,16 @@ Table of Contents
     :maxdepth: 1
     :numbered:
 
-    recipes
     installing
+    recipes
+    recipes_advanced
+    remote_gpio
+    recipes_remote_gpio
+    source_values
+    cli_tools
+    faq
+    contributing
+    development
     api_input
     api_output
     api_spi
@@ -16,17 +24,9 @@ Table of Contents
     api_other
     api_generic
     api_tools
+    api_info
     api_pins
-    api_utils
     api_exc
-    cli_tools
-    source_values
-    remote_gpio
-    recipes_advanced
-    recipes_remote_gpio
-    faq
-    contributing
-    development
     changelog
     license