add dayOfYear method

[nscala-time]

add dayOfYear method

[gakuzzzz]

We can call dayOfYear and withDayOfYear method of DateTime.
The same name methods are unnecessary to define by pimp my library

[tyrcho]

cool, thanks ! the workaround is also OK using underlying.withDayOfYear until this is release.

I just added a note in the commit for a small typo in a method name.

[kmizu]

Hi, @tyrcho

What @gakuzzzz said seems to be misunderstood. What he said is that dayOfYear and withDayOfYearare unnecessary to define in RichDataTime since these methods are already defined in DateTime. And It's not workaround. Then, your pull request is not merged and closed.

RichDateTime is used to add new methods to existent types, it's so-called "pimp-my-library" pattern and RichDateTime itself is not explicitly used usually. If you want to call a method defined in DateTime,
you should call the method defined in DateTime.

If I'm something wrong, let me know about it.