change learning rate in MaxEntSGDLearner
add SVMInvariantUpdateLearner
reduce redundant memory allocation in WeightVector and FeatureVector
update README.md
change learning rate in SVMInvariantUpdateLearner
add SVMASGDLearner and example
change some access modifiers to private in WeightVector and FeatureVector
change seed of Random
trivial fix of WeightVectorTest
add LessRAMWeightVector and test
update README.md