Add (optional) output format for decimal hours

[jotaen]

Currently, the default and canonical output format is the 3h, 15m, or 5h30m notation (as defined by the spec).

The CLI provides a --decimal option, which renders the decimal minutes of all values without suffix/unit, e.g. 180, 15, or 330.

There could be another output format for rendering hour values as decimal-based floating point values, e.g. 3, 0.25, 5.5.

default	minutes (integer)	hours (float)
3h	180	3
15m	15	0.25
5h30m	330	5.5

One caveat about such an “hour”-based floating point format would be that it’s subject to rounding. E.g., 3h34m would yield 3.56666666…. For pragmatic reasons, the precision could be hard-coded, e.g. at two digits.

Flag

The current --decimal flag should probably consolidated with that new output format. Potential solutions:

• (a) Make the --decimal flag take a value, i.e. either min or hour.
• (b) A more generic “output” or “format” flag, that would be used like --format decimal-minutes or --format decimal-hours (or similar), which would implicitly default to the current canonical output format (e.g., --format canonical).