Log Message:
Update 1.4.3 -> 1.5.0

Changes since 1.4.3:

* Removed deprecated TUTORIAL file.
* Removed support for the "showage" configuration variable.
* "task stop" can remove the start time from a started task.
* "task ghistory" now displays a differently aligned graph, allowing
* easier comparison by month of tasks added versus completed and
  deleted.
* "task version" command now reports unrecognized configuration
  variables, which may be spelling mistakes or deprecated variables.
* "configure --enable-debug" now supported to suppress compiler
  optimization to allow debugging.
* Allow lower case priorities, and automatically upper case them.
* Added support for "due" configuration variable which defines the
  number of days in the future when a task is considered due.
* Added support for custom reports, comprised of a set of column names
  and sort order, with optional filtering in the configuration
  file. This means user-defined reports can be written, and the
  reports currently in the configuration file can be renamed. Several
  of task's built in reports have been converted to user-defined
  reports.
* New online documentation for custom reports.
* New algorithm for determining when the "nag" message is displayed.
* Fixed bug where task hangs with a certain combination of recurring
  tasks and shadow files.
* Fixed bug with the task sort algorithm, which led to an unstable
  sequence when there were only a handful of tasks.
* Performance enhanced by eliminating unnecessary sorting.
* Task now has a large (and growing) test suite and bug regression
  tests to help ensure higher quality releases.
* Fixed bug that caused large performance hit during table rendering.
* Fixed bug that concatenated a modified description without spaces.
* Added new column 'recur' that displays the recurrence period of any
  recurring tasks. This column can be added to any custom report.
* Added support for "color.recurring" configuration variable which
  specifies the color of recurring tasks.
* Added support for "locking" configuration variable that controls
  whether file locking is used.
* Task export feature now includes recurrence information, removes
  nested quotes, and limits output to pending tasks.
* Task no longer includes deleted tasks in the summary report (thanks
  to Benjamin Tegarden).
* Fixed bug that prevented the summary report from properly reporting
  recently completed tasks.