Adding option to specify protocols to import when using transformable type

Allows to specify a _attributeValueClassName_ similar to `id<MyProtocol>`
Mogenerator can now insert `@protocol MyProtocol; ` in the machine header files.  Another user info needs to be added where the key is _attributeTransformableProtocols_ and the value is a comma separated list of the protocols used for the type.  For the above example, it would just be MyProtocol as value.