[BUG] Panics, error handling

[LdDl]

Describe the bug There are some log.Panicln(...) calls in code. I do not think that this is good at all. Also error handling is not that good,

To Reproduce nope

Expected behavior nope

Describe the solution you'd like and provide pseudocode examples if you can Every function which can cause error should return it as second returning argument. For example : https://github.com/LdDl/cnns/blob/master/convolutional_layer.go#L104 can call panic when some indices mismatch detected

Additional context nope