Changing Matlab/Octave's svm-train so that it respects -q when doing cross-validation.

Previously, svm_set_print_string_function was in svm.h, but it's mostly useless
for svm-train since the only variable it affects, svm_print_string, is not used
or visible anywhere in svm-train. This makes info now visible on svm.h,
renaming it to svm_info for consistency, and svm-train uses svm_info for its
output, instead of hardcoding mexPrintf.