Add support for native doctrine model autoloading

[MikeSeth]

This is a small patch that extends AgaviDoctrineDatabase? to add configuration parameter model_path so that you can specify the ORM class (Doctrine model) path[s] in configuration and have Doctrine autoload them. Doctrine also supports lazy vs aggressive model loading which can be configured using the attributes configuration in this driver. By default, Doctrine uses the aggressive loading model. In production, you should switch it to lazy loading. See Doctrine manual chapter 1.7 for explanations.

You can specify a single value or multiple <parameter> elements.

Example:

<database name="doctrine" class="AgaviDoctrineDatabase">
 <parameters>
   <parameter name="dsn">mysql://foo@bar/cat</parameter>
   <parameter name="model_path">
     <parameter>%core.app_dir%/db/models</parameter>
     <parameter>%core.lib_dir%/libmylib/doctrine-models</parameter>
   </parameter>
 </parameters>
</database>

[MikeSeth]

Patch against AgaviDoctrineDatabase?

[david]

(In [2537]) Added support for native doctrine model autoloading, closes #759