Modify svm_read_problem in python/svmutil.py so when reading data in libsvm format, zero values are ignored. Some other minor changes to make svm_read_problem same as that in liblinear.
Modify svm_read_problem in python/svmutil.py so when reading data in libsvm format, zero values are ignored. Some other minor changes to make svm_read_problem same as that in liblinear.

cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm,cjlin1/libsvm