Add ability to set account path

Useful for nesting folders etc.
Provide sorted accounts slice
Add citi parser

This parsers citi transaction html pages, because it exposes some info not included in the csv download.
Accept a list of cards per user
Use time.Equal for test
Refactor, change output format
Update test
Invert amount, now positive for debits, negative for credits
Split util.ParseDir functionality for reusability
Make pfin.Transaction.Amount() consistent
Add chase parser
Wrap parser error with account and filename
Fix date spacing hack
Add initial readme
Update cmd/status
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