Segmentation fault in SVD test program

[benlandrum]

Please add usage notes and error messages to the SVD test program. When executed without any arguments, it segfaults.

STKFMM/M2L/svd_test.cpp

Line 104 in 53603c4

const int pEquiv = atoi(argv[1]); // (8-1)^2*6 + 2 points