Bug #860

- Fixed bug #860, which prevented lower-case priority values from being
  accepted (thanks to Michelle Crane).
- Added unit tests.
- Also included ChangeLog updates from other fixes that were misseed.

ChangeLog

@@ -47,6 +47,7 @@
  + Added feature #422, #566 and #639, which allow task modifications during
    'done', 'delete', 'start', 'stop' and 'duplicate' commands (thanks to Max
    Muller).
+ + Added feature #474, which means the 'info' command accepts filters.
  + Added feature #479, which enables filtering for the 'calendar' command.
  + Added feature #496, which allows rc.default.command to be supplemented with
    a filter, so that 'task project:Home' applies the project filter to the
@@ -102,6 +103,8 @@
    Aikido Guy).
 
 # Tracked Bugs, sorted by ID.
+ + Fixed bug #208, which addresses various problems with recurring tasks, and
+   change propagation.
  + Fixed bug #403, which disambiguates certain commands involving numbers.
  + Fixed bug #458, removing the ambiguous 'm' as a duration, leaving 'mi[nutes]'
    and 'mo[nths]' requiring at least two characters for a match.
@@ -139,6 +142,8 @@
    Alexei Romanoff).
  + Fixed bug #720, so that when the 'info' report renders total active time,
    it uses a lossless format (thanks to Bernhard B).
+ + Fixed bug #722, #801, so that all recurring task change propagations are
+   confirmed (thanks to Arkady Grudzinsky).
  + Fixed bug #723, which displayed a misleading message when the output was
    truncated to a page.
  + Fixed bug #732, which fixes misleading messages and documentation for
@@ -190,6 +195,8 @@
    Owen Clarke).
  + Fixed bug #822, #845, which generated incorrect IDs (thanks to Matt Kraai and
    Michelle Crane).
+ + Fixed bug #823, so that recurring task change propagations are now always
+   confirmed (thanks to Miguel de Val Borro).
  + Fixed bug #824, which caused probles when completing recurring tasks (thanks
    to Matt Kraai).
  + Fixed bug #831, which prevented some date fields from being properly parsed.
@@ -205,6 +212,8 @@
    (thanks to Michelle Crane).
  + Fixed bug #859, which used only one color for the 'ghistory.*' report
    legends (thanks to Uli Martens).
+ + Fixed bug #860, which prevented lower-case priority values from being
+   accepted (thanks to Michelle Crane).
  + Fixed bug #862, which suppressed feedback from the 'denotate' command.
 
 # Untracked Bugs, biggest first.