Caffe has dependencies that aren't necessarily universally needed especially when it comes to IO. The installation could be streamlined by making

• leveldb
• lmdb
• hdf5
• and even OpenCV

optional so that the Python or MATLAB interfaces can take care of IO or a client C++ library could handle input.

Of course there is an advantage to having a standard all-in build since input formats and portability can be counted on, but there are cases when it's overkill.

This would need a fleet of build flags and ifdef guards and is perhaps best left until the build has been standardized by work like #1667.

Note that this was first suggested by @kloudkl in #1074 but it was too early and at the time and the build needed to improve before turning our attention to separation.