Create budgets for MIS reports.

This module lets you create budgets for any MIS report. Several budgets can be
created for a given report template (ie one budget per year). Budget figures
are provided by KPI or by GL account, with different time periods. A budget can
then be selected as a data source for a MIS report column, and the report will
show the budgeted values for each KPI, adjusted for the period of the column.
