Utility and Meta Modules

Comment	A module that allows adding comments to Model summaries.
Bias	A simple bias module that adds a (trainable by default) bias array (default) or scalar to the input.
Flatten	Module that flattens the input to 1D.
Reshape	Module that reshapes the input array to a specified shape.
SubsetModule	Meta-module that applies a given module to a subset of the input data and optionally passes the remaining input data through unchanged.
MultiModule	Meta-module that applies multiple modules in sequence.
Func	Module that implements a general element-wise function, optionally with trainable parameters and state.