0.14.0 Event-based ledger

• Event-based ledger introduced
• pyright checks added
• Prose rewite in README.md
• current_earnings better handled
• Restored most tests (1 skipped)

Development ideas:

• re-entry from JSON should be identical
• maybe we duplicate chart in Book
• Book vs Ledger responsibilities

0.10.4 is a candidate release for v1.0

• Complete accounting workflow from chart to entries to reports.
• README.md and readme.py have an end-to-end code example.
• Covered by pytest and mypy.
• Code separated to chart.py, core.py, entry,py and book,py.