cleaned up imports
moved check_cuda to cuda convnet and made its error message customizable
for features other than maxout
factored out some of the initialization from maxout so it's useful for
other convolutional layers
fixed some bugs in the refactor
conv c01b transpose
ImageActs gradient
Merge branch 'master' of github.com:lisa-lab/pylearn2
named arguments to avoid them going to stride
Merge branch 'master' of github.com:lisa-lab/pylearn2

Conflicts:
	pylearn2/linear/conv2d_c01b.py
	pylearn2/models/maxout.py
more support for strides
repaired botched merge
support for not passing output_shape if stride=1
fixed gradient of ImageActs
added Space.batch_size
Merge branch 'master' of github.com:lisa-lab/pylearn2

Conflicts:
	pylearn2/models/maxout.py
Merge pull request #281 from goodfeli/master

refactor of convolution code