handle payments

[Sha-yol]

Currently, payments "expenses" are skipped. I suggest handling them in the following way:

• If the balance account feature is off, add/subtract the payment amount from the account with the correspond withdrawal/deposit txn
• If the balance account feature is off, add a transfer txn to/from the balance account to the corresponding account.

[adyanth]

For 1, matching/searching the old transaction might be tricky (or maybe not, since dedup does the same).
For 2, feature is off on.

Sounds good to me.