Add various layer types

[dhruvrajan]

• Conv2D
• LSTM
• Dropout
• Flatten
• MaxPool2D

[zaleslaw]

I could help with Conv2D or different pooling for example (implemented them in private project)

[Sciss]

How difficult is this to implement? I'm looking for

• BatchNormalization
• LeakyReLU
• Reshape
• Conv2DTranspose
• Dropout

[zaleslaw]

@Sciss please have a look at the KotlinDL library