Mentioned infinite precision arithmetic
Refactoring for Detailed Transactions

* Don't record the date of each detailed transaction; derive it from the
parent
* Record the result amount of a detailed transaction
Support for book reports
better formatting of book report

Compute max name length of all accounts so that they are justified
across all report sub-groups.
write reports to both file and stdout
Don't write Markdown code blocks to stdout
Updated example with book type of report