Allow .dates(date) and .range(date) single dates.
Implement summarize.
Tasks.
Summarize: tests.
Formatter: fix %i not stripping decimals.
DefaultReporter: summarize.
DefaultReporter: show heading.
JsonReporter: summary.
Man pages.
Bin: mention 'summary'.
DefaultReporter: show '<1h' instead of '0h'.
Tasks.
Update docs.
Update Makefile.
Man: updates.
Man: add 'man timetip'.
Document offsets.
Man: update.
Simplify --help.
Bin: simplify --help again.