journal files can now include journal, timeclock or timedot files (but
not yet CSV files). Also timeclock/timedot files no longer support
default year directives.
The Hledger.Read.* modules have been reorganised for better reuse.
Hledger.Read.Utils has been renamed Hledger.Read.Common and holds
low-level parsers & utilities; high-level read utilities have moved to
Hledger.Read.
Use slightly clearer m4 macros instead of special divs to mark content
as web only/man only. The temporary doc/*.md files are no longer needed,
slightly more redundant work is done.
