Merge pull request #302 from goodfeli/master

Small, misc
Library Documentation
more doc
add linear and cuda-convnet
best svhn model files added
PEP8
Better error handling.
Implemented masked_fprop.
Code for computing the exhaustive geometric mean.
Added a test of masked_fprop.
Docstring from masked_fprop.
Merge pull request #308 from dwf/exhaustive_model_average

Exhaustive model averaging with dropout
Fix assertion.
Added/refactored sampling and exhaustive functions, tests.
Merge pull request #307 from memimo/svhn-results

Maxout's best SVHN model files and desc added
Merge pull request #305 from memimo/doc

Added some autodocs for library documentation
Merge pull request #309 from dwf/dropout_averaging

Dropout averaging
Added the four regions benchmark.
Merge pull request #310 from dwf/four_regions

Added the four regions dataset.
Fix doc syntax