Improve between_time to be able to select time ranges that cross midnight

[wesm]

inspired by: http://stackoverflow.com/questions/12041519/how-to-get-the-mean-of-a-specific-span-of-time

[yeyeric]

hello,
is there any solution to this ? it's not clear to me whether this has been implemented, and setting end_time before start_time ends in another behaviour than considering it being the day after. I managed to get through this by splitting my intervals at midnight but was wondering if there was something in pandas ?