[DDC-2335] Add note about filtering schema by regexp expression to relevant commands help output.

lib/Doctrine/ORM/Tools/Console/Command/ConvertMappingCommand.php

@@ -98,6 +98,12 @@ semantical operations on associations such as cascade.
 <comment>Hint:</comment> There is no need to convert YAML or XML mapping files to annotations
 every time you make changes. All mapping drivers are first class citizens
 in Doctrine 2 and can be used as runtime mapping for the ORM.
+
+<comment>Hint:</comment> If you have a database with tables that should not be managed
+by the ORM, you can use a DBAL functionality to filter the tables and sequences down
+on a global level:
+
+    \$config->setFilterSchemaAssetsExpression(\$regexp);
 EOT
         );
     }

lib/Doctrine/ORM/Tools/Console/Command/SchemaTool/CreateCommand.php

@@ -55,6 +55,12 @@ class CreateCommand extends AbstractCommand
         ))
         ->setHelp(<<<EOT
 Processes the schema and either create it directly on EntityManager Storage Connection or generate the SQL output.
+
+<comment>Hint:</comment> If you have a database with tables that should not be managed
+by the ORM, you can use a DBAL functionality to filter the tables and sequences down
+on a global level:
+
+    \$config->setFilterSchemaAssetsExpression(\$regexp);
 EOT
         );
     }

lib/Doctrine/ORM/Tools/Console/Command/SchemaTool/DropCommand.php

@@ -64,6 +64,12 @@ class DropCommand extends AbstractCommand
         ->setHelp(<<<EOT
 Processes the schema and either drop the database schema of EntityManager Storage Connection or generate the SQL output.
 Beware that the complete database is dropped by this command, even tables that are not relevant to your metadata model.
+
+<comment>Hint:</comment> If you have a database with tables that should not be managed
+by the ORM, you can use a DBAL functionality to filter the tables and sequences down
+on a global level:
+
+    \$config->setFilterSchemaAssetsExpression(\$regexp);
 EOT
         );
     }

lib/Doctrine/ORM/Tools/Console/Command/SchemaTool/UpdateCommand.php

@@ -93,6 +93,12 @@ task will drop all database assets (e.g. tables, etc) that are *not* described
 by the current metadata. In other words, without this option, this task leaves
 untouched any "extra" tables that exist in the database, but which aren't
 described by any metadata.
+
+<comment>Hint:</comment> If you have a database with tables that should not be managed
+by the ORM, you can use a DBAL functionality to filter the tables and sequences down
+on a global level:
+
+    \$config->setFilterSchemaAssetsExpression(\$regexp);
 EOT
         );
     }