Budget and paid in advance.

Hi there, firstly thank you for this app to community.

1 - Budgets: Will be absolutely awesome to build budgets from the app, and convert into invoices.

We can't do it from invoices because it automatically generate a correlative number of invoice.

2 - Paid in advance: Many works have to pay some % in advance to accept budgets. Will be awesome if we can use it to add this receipts to clients, and after add to final invoice as already paid.

3 - Recurrent payments: Some services are paid monthly, and anually. Will be awesome if we can add this kind of invoices.

4 - Add conditions to budgets.