Added support for callable template variables
Fixed placeholder image in gallery object
Do not check model type if using relations
Fixed missing method parameters
Use the product type class when adding product to collection
Frontend modules now pass a config array to the product

So the product must not know about the field names or sources
for configuration in the modules
Added attribute for base price calculation
Added closure to product template to generate an attribute
Added closure to retrieve a gallery object to product template
Media manager cannot be generated
Price is added to the template directly in the generate() method

Only temporary until we find a better solution
Do not generate product attributes, the template does that