* softplus inplace * softplus inplace add src/tests CMakeLists.txt * Update CMakeLists.txt * Update softplus.cpp * Update softplus.h * Update softplus.cpp * Update test_softplus.cpp * Update softplus.cpp * Update softplus.h Co-authored-by: sf <sf@sf.sf> Co-authored-by: nihui <shuizhuyuanluo@126.com>