Implemented unrolling of RNNs and various new layers
- Added full support for recurrent networks using the unroll mechanic.
- Added various new layers, including ArgMax, BeamSearch, BroadcastAdd, BroadcastMultiply, Dot, ExpandDims, GreedySearch, ReduceSum and Repeat. Adjusted Reshape layer to fit backend implementation.
- Added and adjusted multiple CoCos and tests to add support for the layers as well as the unroll mechanic.