- Upstream update from 3.13 to 3.17
  svm.c and svm.h:
    add sv_indices in model structure, so users can know which training instances are SVs
    two library funs svm_get_sv_indices and svm_get_nr_sv are added
    max_iter warning moved to stderr so -q won't disable it
  svm-train.c:
    usage modified to stress that multiclass is supported
  svm-predict.c:
    add -q for svm-predict
  svm-scale.c:
    issue a warning if feature indices do not start from 1
    issue a warning for inconsistency between scaling-factor file and input file
  tools:
    subset.py is written to be much faster
  fix the bug of not freeing sv_indices
  tools/grid.py:
    -null option: allow the search on C or g only
    -resume option: resume tasks from an earlier run
     can be called as a python module
  python interface:
    local package searched first
  libsvm options can be str or list
  param.show() becomes print(param)
  tools/:
    easy.py fails in 3.15. Fix it by modifying grid.py
  svm.cpp:
    if class labels are 1 and -1, ensure labels[0] = 1 and labels[1] = -1
    initialize model->sv_indices as null in svm_load_model
    if nr_fold > # data, change nr_fold to be # data and ro leave-one-out cv
  matlab interface:
    handle the problem where output variables are not specified