Bulk

- Modified the meaning of 'rc.bulk'.  The old meaning was: the largest number
  of tasks that could be modified without confirmation.  New meaning is: the
  number of tasks that trigger bulk confirmation.  Default was 2 (meaning that
  2 tasks affected were not in need of confirmation), is now 3 (meaning 3 tasks
  now trigger confirmation.
  Despite the dog's dinner I made of the preceding statement, the configuration
  variable is now easier to understand.

src/Config.cpp

@@ -89,7 +89,7 @@ std::string Config::_defaults =
   "indent.report=0                                # Indent spaces for whole report\n"
   "row.padding=0                                  # Left and right padding for each row of report\n"
   "column.padding=1                               # Spaces between each column in a report\n"
-  "bulk=2                                         # > 2 tasks considered 'a lot', for confirmation\n"
+  "bulk=3                                         # 3 or more tasks considered a bulk change and is confirmed\n"
   "nag=You have more urgent tasks.                # Nag message to keep you honest\n"                      // TODO
   "search.case.sensitive=yes                      # Setting to no allows case insensitive searches\n"
   "active.indicator=*                             # What to show as an active task indicator\n"