Bug 23408

Color
- 256-color support, for more interesting and subtle color control.
- Color 'blending' which is the mixing of foreground and background colors for when multiple color rules apply.
- Alternating line coloration.
- Color rules now match on partial project names, like filters.
- The 'color' command now allows you to test various color combinations ("task color red on rgb315")

Calendar
- Calendar report can now list due tasks beneath the calendar.
- Holidays can now be marked on the calendar.

Configuration
- New 'config' command to modify your .taskrc file, report on the current configuration, and check your .taskrc file for problems.
- Ability to nest configuration files with the "include" keyword.
- More data format options, including the ability to control date format by report.
- More control over the display of annotations.
- Ability to include the date and time on certain fields.
- New 'countdown' report column showing time until task is due.
- Several other new report columns.
- More control over calendar colors.
- Ability to color tasks due today differently, to make them stand out.
- Configurable case-sensitivity for searches, subsitutions.
- Configurable tag-, recurrence- and active-indicators.

Documentation
- New task-faq man page.
- New task-color man page explaining color usage.
- Updates to all man pages.

Filters
- New 'word' and 'noword' attribute modifiers.

Miscellaneous
- More vim syntax highlighting of task data files and configuration files.
- Lots of bug fixes, and a huge increase in the size of the test suite, for improved quality.