polished ignore
add Adopt{Data,Diff} methods to blobs to enable "virtual copying"
change Adopt -> Share as suggested by kloudkl
sigmoid layer backward pass optimization: don't recompute forward pass
Merge pull request #319 from jeffdonahue/sigmoid-optimization

sigmoid layer backward pass optimization: don't recompute forward pass
Merge pull request #318 from jeffdonahue/blob-copy-by-reference

add Share{Data,Diff} methods to blobs to enable "virtual" copies

- reduce operations by not copying values
- spare memory by shared_ptrs
- simplify SplitLayer logic
Add possibility to use OpenBlas
Merge pull request #325 from AlOa/OpenBlas

Add possibility to use OpenBlas
rename python include config var to match lib
Give choice of ATLAS, MKL, and OpenBLAS (with option to override paths)

- configure build for ATLAS, MKL, or OpenBLAS on Linux and OSX
- allow overriding of the include or lib dirs
- replace magic numbers with BLAS names (atlas, mkl, open)

Follow-up from #305 and #325.
rename lenet dir to mnist
define AlexNet architecture

Swap order of lrn and max pooling layers to reflect Krizhevsky
architecture. Initialize biases to 0.1 where Krizhevsky had 1, as
training by initialization with 1 has flat loss.
Document AlexNet model, include download script
include pretrained snapshot and performance details
add mnist autoencoder example necessities (sigmoid cross entropy loss
layer, sparse gaussian filler)
enable DataLayer to output unlabeled data
mnist autoencoder test proto bugfix: add sigmoid layer before loss
make solver able to compute and display test loss
change lenet dir to 'mnist' in docs
mnist_autoencoder_solver cleanup