Added missing requirements

dlib/dnn/cudnn_dlibapi.h

@@ -281,6 +281,8 @@ namespace dlib
             /*!
                 requires
                     - is_same_object(dest,src) == false
+                    - src.nr() >= stride_y
+                    - src.nc() >= stride_x
                 ensures
                     - #dest.num_samples() == src.num_samples()
                     - #dest.k() == src.k()

dlib/dnn/curand_dlibapi.h

@@ -41,6 +41,7 @@ namespace dlib
             /*!
                 requires
                     - data.size()%2 == 0
+                    - stddev >= 0
                 ensures
                     - Fills data with random numbers drawn from a Gaussian distribution
                       with the given mean and standard deviation.