protect tester calls with pcall.
New NN classes
extra/nn/L1Cost.lua                       : L1 penalty
extra/nn/SpatialFullConvolution.lua       : full convolution
extra/nn/SpatialFullConvolutionMap.lua    : full convolution with connection table
extra/nn/TanhShrink.lua                   : shrinkage with x-tanh(x)
extra/nn/WeightedMSECriterion.lua         : mean squared error with weighting mask on the target

Add new nn classes that are used commonly for unsupervised training of convolutional auto encoders
unsup does not depend on kex anymore.