started tuple_var
expose Dataset from pylearn2.datasets
make invert a general method of Preprocessor instead of just ZCA
make ZCA_Dataset support not having targets
doc
Composite and Flattener layers
added 'return_all' flag to S3C.random_design_matrix
better error messages
support for monitoring datasets that only support random iteration (such
as infinite data streams)
more complete implementation of CompositeSpace
made sgd support monitoring datasets that don't support sequential
iteration
made SGD make right kind of variable for model's output
more non-sequential iteration support
added a date to a deprecation warning