Budget's start date reset on file load

[hsoft]

When saving and reloading a file, a budget's start date are reset to the first day of the current month.

[hsoft]

[milestone:id#51179 bulk edit command]

[hsoft]

(from [141]) [#79 state:fixed] Had the start_date included in the save/load process (as well as stop_date + interval. man did I not test this budget feature before releasing 1.6....). Also, fixed a bug where the repeat_type selector would sometimes have the -1 index initially selected on panel load