* _forward is renamed forward since users should override it
* some __call__ overrides are changed to forward
* function which return a single variable are changed to return that
variable instead of a one-element tuple
- nn.Container.modules is just a python list and used by nn.Sequential
- Every module in nn.Sequential has a name. This fixes Module.type()
- nn.Sequential constructor accepts either a list or an OrderedDict. With a
list, the modules are named "0", "1", "2", ...
