Add sub-sections for autoload docs

doc/04-schema.md

@@ -354,11 +354,13 @@ Example:
 
 Autoload mapping for a PHP autoloader.
 
-Currently [PSR-0](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md)
+Currently [`PSR-0`](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-0.md)
-autoloading, classmap generation and files are supported. PSR-0 is the recommended way though
+autoloading, `classmap` generation and `files` are supported. PSR-0 is the recommended way though
 since it offers greater flexibility (no need to regenerate the autoloader when you add
 classes).
 
+#### PSR-0
+
 Under the `psr-0` key you define a mapping from namespaces to paths, relative to the
 package root. Note that this also supports the PEAR-style non-namespaced convention.
 
@@ -406,6 +408,8 @@ use an empty prefix like:
         }
     }
 
+#### Classmap
+
 The `classmap` references are all combined, during install/update, into a single
 key => value array which may be found in the generated file
 `vendor/composer/autoload_classmap.php`.
@@ -422,6 +426,8 @@ Example:
         }
     }
 
+#### Files
+
 If you want to require certain files explicitly on every request then you can use
 the 'files' autoloading mechanism. This is useful if your package includes PHP functions
 that cannot be autoloaded by PHP.