Generate multi-class constraints for a number of binary classifiers automatically

[kordjamshidi]

Currently, we use the SparesNetworks implemented in LBjava directly for the multi-class classification. To have more flexibility in the weight updates for the multi-class setting, specially for the joint training we better to do implement multi-class setting based on the binary classifiers and constraints.

[danyaljj]

Easy way to generate constraint classifiers for sequence tagging.