added code to test box.cpp (right now, just looking for the failure we saw
where the find_box does not return the appropriate box)
fixed silly bug
added potentially useful print statement
fixed typo
test_box was not causing the error

it is possible that the problem arose because gaussian_process
decided not to do a new search, and just used the cached search
(I can probably implement a better dosrch test)

I have modified the warning message in gaussian_process to reflect
this possibility.  I will now run s_curve and see if the error
reappears