Ajax cascading / URL empty value

Dear finder team,

I have some correction to suggest:
- Ajax cascading: it was not possible to reduce some selection list with cascading effect;
- URL empty value: when you defined the parameter for empty value in the URL (i.e.: '+'), it was not take into account when searching and creating the pager navigation.

Below you can find the patchs.

Best regards,
Emilien MOREL