Updated documentation to include instructions to install protobuf with Python support on Mac OS X
Updated installation docs for OS X 10.9 brew install protobuf as well
Refactor DataLayer using a new DataTransformer

Start the refactoring of the datalayers to avoid data transformation
code duplication. So far, only DataLayer has been done.
clean up cpu signbit definition

The redundant "caffe_signbit" function was used as a circumlocution
around CUDA's signbit macro; we can just add extra parens to prevent
macro expansion.
specialize cpu_strided_dot before instantiation to fix clang++ build
Refactor ImageDataLayer to use DataTransformer
Merge pull request #956 from longjon/clean-signbit

Clean up CPU signbit definition
Merge pull request #942 from yosinski/doc-update

protobuf should be installed with Python support on Mac
If specified, --gpu flag overrides SolverParameter solver_mode.
Merge pull request #961 from jeffdonahue/gpu-flag-overrides-solver-mode

If specified, --gpu flag overrides SolverParameter solver_mode.
Merge pull request #954 from geenux/dev-redundant-data

Refactor data layers to avoid duplication of data transformation code
restore old data transformation parameters for compatibility
compact net parameter upgrade
upgrade net parameter data transformation fields automagically

Convert DataParameter and ImageDataParameter data transformation fields
into a TransformationParameter.
upgrade model definitions for transformation params
Merge pull request #963 from shelhamer/fix-transform-param

Make data transformations backwards-compatible and upgrade models
fix parameter for transformation in ImageDataLayer constructor
move {InnerProduct,Eltwise}Layer to common instead of vision
fix internal thread interface confusion

thanks @ronghanghu for pointing this out in #964
[example] add fully-convolutional efficiency note + confidence map

- spell out fully-convolutional efficiency
- add confidence map
- fix input size: 451 x 451 is correct for an 8 x 8 output map by the
  equation input size = 227 + 32(d-1) for output map dimension of d