Revert "Merge pull request #114 from jeffdonahue/dags-by-split"

Revert dags-by-split merge because split layers were not quite ready.
Sorry for the bug!

We are adopting a `master`/`dev` split development
model, where new commits and pull requests will be merged to `dev` for
testing before integration to `master`. This will keep master clean and
stable.

This reverts commit d339d242b43ec5bec9dceb657ee0d665d524b1eb, reversing
changes made to 55198262d79944fa7382868f7ecd108ed4f238a2.
Merge pull request #123 from longjon/master

don't pass LDFLAGS when only performing compilation (-c)
fix detector's coordinate mapping for images smaller than IMAGE_DIM
Properly index windows in detector list mode

Fix iteration over single windows: whether one or more windows are
listed for an image, generate windows as a list.
Moving gh-pages docs to docs/ folder, with script to build them
improved docs-building script
Safer docs/ build process: into own folder
Updated README with doc info
Merge pull request #157 from sergeyk/master

Moving gh-pages stuff to docs/ directory, with script to build and deploy to gh-pages.
more instructions on how to contribute
More comments in Makefile.config.example
minor README fix
Set leveldb options.max_open_files = 100. Fix #13 and #38
Merge pull request #154 from sguada/leveldb_max_open_files
Fix error message typo in SoftmaxWithLossLayer
Merge pull request #164 from t-abe/fix-typo
move imagenet splits + synsets to data
add imagenet mean file
file mnist
Make tools/ for core binaries, stow scripts/ in tools/extra

Collect core Caffe tools like train_net, device_query, etc. together in
tools/ and include helper scripts under tools/extra.