average balance graph incorrect

[Ben Stanley]

package: average balance report
version: cvs 26 March

I performed an average balance report on an account that went negative
over 3 transactions in one place, but the report showed me that the
account was negative three separate times.

On comparison to the data in the ledger, the graph appeared to be
completely and totally inacurate, bearing only a mild resemblance to the
movement of the numbers.

This report needs some validation work.