Simplify LogSoftmax (#218)
Simplify LogSoftmax (#218)


Former-commit-id: 642e7acd22373f090d3756818005a93122aebd65
shuheik/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,chunyang-wen/dynet,xunzhang/dynet,clab/dynet,chunyang-wen/dynet,shuheik/dynet,danielhers/dynet,shuheik/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,clab/cnn,shuheik/dynet,shuheik/dynet,xunzhang/dynet,clab/cnn,shuheik/dynet,xunzhang/dynet,clab/cnn,shuheik/dynet,chunyang-wen/dynet,clab/dynet,clab/dynet,clab/dynet,xunzhang/dynet,clab/dynet,danielhers/dynet,danielhers/dynet,chunyang-wen/dynet