Added some Atom_new() timing code to see if changing NUM_BUCKETS from a power
of two to a prime would make a difference. Had to define _POSIX_C_SOURCE to get
access to the POSIX high-resolution timeing functions. See
feature_test_macro(7) and clock_gettime(3) for more info.

Used strings from Mark Twain's "The Adventures of Huckleberry Finn"