Wrap parser error with account and filename
Rename util.TxString to FormatTx, refactor, move Fields to util
Move pfin.TxString to util, add formatting functions
Add parser/all metapackage, add category to other parsers
cmd/unpaid: Refactor, add category totals
cmd/unpaid: Sort transactions by date, calculate paid and total, skip account and user
cmd/unpaid: Make separator configurable
Add category to transaction interface and some parsers
Combine root and account paths in ParseDir
Move ParseDir to pfin/util, rework cmd/main filters
pfin/util: Add StringFilter
Add filename to Parse interface, use it for personal accounts
cmd/main: Add some basic filters
Support setting default user per account
Expose account name in transaction interface