HDR+ Implementation

Please see: http://timothybrooks.com/tech/hdr-plus

To compile, follow these steps:

1. Install Halide from http://halide-lang.org/.
2. Set HALIDE_ROOT_DIR in CMakeLists.txt to the Halide directory path.
3. Install dcraw and add it to PATH. Source code available at https://www.cybercom.net/~dcoffin/ or just do

apt-get install dcraw

4. From the project root directory, run the following commands:

mkdir build
cd build
cmake ..
make