FileTask: Return a late timestamp instead of an early timestamp if the
file does not exist.  This should fix issue #286.
Update our monkey patch of Time#<=> to consider Rake::LateTime.
This makes the tests pass on Ruby 1.8.7.
Merge pull request #287 from DavidEGrayson/pull_request_1

FileTask: Return a late timestamp instead of an early timestamp if file doesn't exist