Timedelta to businesshours support

[csoare7]

First of all, thank you very much for your work on this library.

I found myself slightly confused when trying to extract business hours from the timedelta result.

>>> d1 = datetime.datetime(2017, 5, 23, 9, 0)
>>> d2 = datetime.datetime(2017, 5, 24, 9, 0)
>>> r = BusinessTime().businesstimedelta(d1, d2)
datetime.timedelta(1)

My immediate thought to extract the business hours (which in this case it's 8) was to call
timedelta.total_seconds() method on the result, but this will return the equivalent of 24 hours in seconds, not 8 hours - given it has no knowledge of the business_hours in the BusinessTime object.

This experience proved a bit confusing and was wondering if you might be able to suggest a solution to this? Would a PR would be accepted for this sort of functionality?

[josegonzalez]

Go for it.