The idea of this exercise is to implement an efficient routine for dividing one
time interval by another, with the restriction that the only operations that may
be performed on the intervals are addition, subtraction, and multiplication by
an integer. The time intervals themselves are represented by a TimeInterval
class, which may not be modified.

We're looking for an implementation of the "divide(...)" function in the
interval_tests.cpp file, along with a set of tests to verify the correctness of
the divide(...) function. The tests may be implemented directly in the main
function in the interval_tests.cpp file or in their own functions.

Comments in the divide(...) function should be sufficient to convince a code
reviewer that the function is correct for all possible inputs.

Additionally, the method used to implement interval division in the divide(...)
function should be as algorithmically efficient as possible. In climate
simulations, intervals as large as several millenia may be involved, and in
weather research, intervals as small as a fraction of a second are frequently
used.