Allow forecast of cash flow

[albertocottica]

Right now, it is not clear how I can plan for money to come in. Because:

• The end date in the "Overview" sheet (B4) is computed from the "Status" sheet.
• Adding an invoice with 100% probability in the "Status" sheet does take care of the end date of the project, but still I do not see the chart going up.

[tanius]

Cash flow forecasting is implemented in the most recent version (Budget Spreadsheet v3) now. Which is not yet here in the repository but so far only available as a Google Spreadsheet, but we'll publish it here as well shortly.