add support to file extension on exports and exposers

src/exposers/types/class-tainacan-type.php

@@ -9,6 +9,7 @@ namespace Tainacan\Exposers\Types;
 abstract class Type {
 	
 	protected $mappers = true; // List of supported mapper, leave true for all
+	protected $extension = 'tnc'; // extension sufix for multi operation system compatibility
 	
 	/**
 	 * Change response after api callbacks
@@ -19,7 +20,14 @@ abstract class Type {
 	 */
 	public abstract function rest_request_after_callbacks( $response, $handler, $request );
 	
+	/**
+	 * Return list of supported mappers for this type 
+	 */
 	public function get_mappers() {
 		return apply_filters('tainacan-exporser-type-mappers', $this->mappers, $this);
 	}
+	
+	public function get_extension() {
+		return $this->extension;
+	}
 }

src/exposers/types/class-tainacan-xml.php

@@ -7,6 +7,13 @@ namespace Tainacan\Exposers\Types;
  *
  */
 class Xml extends Type {
+	/**
+	 * {@inheritdoc}
+	 * @see \Tainacan\Exposers\Types\Type::extension
+	 * @var string
+	 */
+	protected $extension = 'xml';
+	
 	/**
 	 * 
 	 * {@inheritDoc}