Description:
------------
When parsing strings containing only a year, it appears that certain ranges of years do not get parsed appropriately. This is a cause, at least in my case, of very difficult to debug errors.

Test script:
---------------
echo var_export(date_parse('1999'), true)."\n\n";
echo var_export(date_parse('2001'), true);

Expected result:
----------------
array (
  'year' => 1999,
  'month' => false,
  'day' => false,
  'hour' => false,
  'minute' => false,
  'second' => false,
  ...
)

array (
  'year' => 2001,
  'month' => false,
  'day' => false,
  'hour' => false,
  'minute' => false,
  'second' => false,
  ...
)

Actual result:
--------------
array (
  'year' => 1999,
  'month' => false,
  'day' => false,
  'hour' => false,
  'minute' => false,
  'second' => false,
  ...
)

array (
  'year' => false,
  'month' => false,
  'day' => false,
  'hour' => 20,
  'minute' => 1,
  'second' => 0,
  ...
)