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.

src/commands/Command.cpp

@@ -466,6 +466,12 @@ void Command::modify_task (
             }
           }
 
+          // Priorities are converted to upper case.
+          else if (name == "priority")
+          {
+            task.set (name, upperCase (value));
+          }
+
           // Dates are special, maybe.
           else if (column->type () == "date")
           {