ManyToMany on Producto

	modified:   app/config/parameters.yml
	modified:   src/BGR/Serrano/ProductoBundle/Controller/ProductoController.php
	modified:   src/BGR/Serrano/ProductoBundle/Entity/ProductoRepository.php
	new file:   src/BGR/Serrano/ProductoBundle/Entity/ProductoUnidadDeMedida.php
	new file:   src/BGR/Serrano/ProductoBundle/Entity/ProductoUnidadDeMedidaRepository.php
	modified:   web/BGR/View/ProductoViewModel.js