Merge branch 'exp/feature-buckets' into 'master'

lib/libstereo/CMakeLists.txt

lib/libstereo/include/stereo.hpp

lib/libstereo/middlebury/algorithms.hpp

lib/libstereo/src/algorithms/clustersf.cu

lib/libstereo/src/array1d.hpp

lib/libstereo/src/bucket1d.hpp

lib/libstereo/src/bucket2d.hpp

lib/libstereo/src/filters/focal_cluster.hpp

lib/libstereo/src/filters/salient_gradient.hpp

lib/libstereo/src/util.hpp