Fix #6075 Balance being miscalculated

[IonAgorria]

And probably fixes #6515 too (not sure)
The bug is that the base balance for the first line in the list is obtained by doing a sum of previous records that are previous date value than first line in list.
It works except when there are several records in the same day and the list is split between records of same day, the records previous than current line but same day are not accounted in balance, the solution is to loop the remaining records in the day to get the proper balance

[braito4]

👍

[eldy]

Thanks for analysis and solution.
I pushed a more complete fix. Because, the sort is done on datev, dateo, rowid, we must keep the same 3 fields to find what are the previous record.