Add condensed output format

[igneus]

As specified in the project roadmap:

condensed format (but with detailed information) suitable for awesome/i3 toolbars etc.

It should fit all important information regarding a liturgical day in a single line of no more than 30 characters (the less the better) and be well readable even with colours disabled.

While it's mostly intended for displaying single-day date ranges, it should produce meaningful (not necessarily beautiful) output for any valid date range.

Where to start: For existing output formats see features/main_modes.feature (commonly used output formats can be invoked by dedicated options) and features/machine_readable_output.feature (any output format can be invoked by the --format= option).

[igneus]

Done in c08b351