Bug #1022

- Fixed bug #1022, where dependencies were note released when a blocking task
  was completed (thanks to Arkady Grudzinsky).
- The Task object now caches ::is_blocked and ::is_blocking Booleans that are
  determined on pending.data load.
- Simplified and sped up color rule processing using cached values, reducing
  the number of map lookups, and removed loop invariants when the rules are
  not defined.
- Simplified urgency calculations given the cached values for blocked/blocking.
- On load, pending.data is scanned for accurate blocked/blocking status
  determination.
- Obsoleted and removed complex single-task dependency calculations.
- Sped up 'nag' processing by using cached values..
- Modified the 'show' command to consider color.blocking to be valid.
- Added default config value for color.blocking, and included it in the
  precedence list ahead of blocked, as it is more important.
- Updated taskrc.5 man page to include the new color.blocking rule, and its
  place in the rule precedence.

NEWS

@@ -1,5 +1,5 @@
 
-New Features in taskwarrior 2.0.1
+New Features in taskwarrior 2.1.0
 
   - The new 'project.indented' format is available and used in the 'projects'
     and 'summary' commands.
@@ -12,18 +12,19 @@ New Features in taskwarrior 2.0.1
   Please refer to the ChangeLog file for full details.  There are too many to
   list here.
 
-New commands in taskwarrior 2.0.1
+New commands in taskwarrior 2.1.0
 
   - New 'ready' report that lists tasks ready for work, sorted by urgency.
   - New 'udas' command shows UDA details and warnings.
   - New '_udas' helper command lists UDA names for completion purposes.
 
-New configuration options in taskwarrior 2.0.1
+New configuration options in taskwarrior 2.1.0
 
   - urgency.scheduled.coefficient
   - color.scheduled
+  - color.blocking
 
-Newly deprecated features in taskwarrior 2.0.1
+Newly deprecated features in taskwarrior 2.1.0
 
   - None