vendor prefix plugin namespace

As suggested by @micgro42 the plugin namespace should use a vendor
prefix to avoid name clashes when DokuWiki is integrated with other
software.

inc/load.php

@@ -111,15 +111,11 @@ function load_autoload($name){
         return true;
     }
 
-    // our own namespace
+    // namespace to directory conversion
     $name = str_replace('\\', '/', $name);
-    if(substr($name, 0, 9) == 'dokuwiki/') {
-        require substr($name, 9) . '.php';
-        return true;
-    }
 
     // plugin namespace
-    if(substr($name, 0, 7) == 'plugin/') {
+    if(substr($name, 0, 16) == 'dokuwiki/plugin/') {
         $name = str_replace('/test/', '/_test/', $name); // no underscore in test namespace
         $file = DOKU_PLUGIN . substr($name, 7) . '.php';
         if(file_exists($file)) {
@@ -128,6 +124,12 @@ function load_autoload($name){
         }
     }
 
+    // our own namespace
+    if(substr($name, 0, 9) == 'dokuwiki/') {
+        require substr($name, 9) . '.php';
+        return true;
+    }
+
     // Plugin loading
     if(preg_match('/^(auth|helper|syntax|action|admin|renderer|remote)_plugin_('.DOKU_PLUGIN_NAME_REGEX.')(?:_([^_]+))?$/',
                   $name, $m)) {