to_clipboard wrong linebreaks on Windows
Copying dataframe with to_clipboard and Qt gives different results: when pasted to Excel there's one more empty line. It may be unexpected and overwrite important data.

When looking into clipboard with Free Clipboard Viewer we can see that Qt uses CR+LF linebreaks:
![image](https://cloud.githubusercontent.com/assets/53390/11464671/d8a13576-9742-11e5-879f-9a288694a344.png)
and pandas uses LF:
![image](https://cloud.githubusercontent.com/assets/53390/11464701/2f5bb8be-9743-11e5-8680-273b4b00bcdf.png)
Maybe this is the source of problem.

(This isn't fixed by #9693)
