Autoload improvments

* Cache all autload files into one cache file to remove any file_exist calls against non existing files during execution
* Lazy load ezcBase so that cached pages that does not use it don't get the overhead (also file_exist calls against non existing files)


Further possible improvement, add support for fallback to simple autoload convention loading if class name starts with "ezp\":

    diff --git a/autoload.php b/autoload.php
    index 245dba3..aefb498 100644
    --- a/autoload.php
    +++ b/autoload.php
    @@ -73,6 +73,12 @@ class ezpAutoloader
             {
                 return require( self::$ezpClasses[$className] );
             }
    +
    +        // Fallback to loading class by convention if it starts with ezp\ namespace
    +        if ( strncmp( $className, 'ezp\\', 4 ) === 0 )
    +        {
    +            return require( str_replace( array('\\', '_'), DIRECTORY_SEPARATOR, $className ) . '.php' );
    +        }
         }
     
         /**