Output of records post filtering

[Riebart]

Support at least the following outputs:

• JSON/YAML/JSON-compact format, for raw dumping of data
• CSV output, suitable for Excel
• Directly rendering the week/day/month in the terminal using ASCII characters in a grid. THis will make it easiest to visualize time spent on things, perhaps using colours to indicate tag similarities and tag sets. So if there are groupings or clusterings of tags, each cluster would be assigned a separate portion of the hue spectrum, and additional... The clustering algorithm for that might be non-trivial, but the output format even with arbitrary colours is useful.

[Riebart]

CSV output supported by tt ls as of c00a375 .

[Riebart]

Basic human-friendly output as of 244c618 .