Bring parts of dev @ 25.02.14 into master

Bring some of the latest developments into the fold as of the witching hour Feb. 25 '14.

- Sort out the dir structure of Caffe #142 
- Model DAGs by split layers #114 #129 
- Fix LevelDB creation snags due to file counts #154 
- Add hyperbolic tan layer #116 
- Fix comment in SoftmaxWithLoss #164