Fix warnings in outofcore/outofcore_cloud.h

> outofcore_cloud.h:158:29: warning: comparison of integers of different signs: 'int' and 'boost::uint64_t' (aka 'unsigned long') [-Wsign-compare]
> outofcore_cloud.h:163:26: warning: comparison of integers of different signs: 'uint64_t' (aka 'unsigned long') and 'int' [-Wsign-compare]
Fix warnings in outofcore/outofcore_viewer.cpp

> outofcore_viewer.cpp:137:11: warning: unused variable 'MAX_DEPTH' [-Wunused-const-variable]
> outofcore_cloud.cpp:316:23: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in outofcore/scene.cpp

> scene.cpp:31:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> scene.cpp:45:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> scene.cpp:63:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in outofcore/viewport.cpp

> viewport.cpp:147:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> viewport.cpp:161:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> viewport.cpp:192:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in features/integral_image_normal.hpp

> integral_image_normal.hpp:1034:29: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> integral_image_normal.hpp:1041:29: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> integral_image_normal.hpp:1078:29: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> integral_image_normal.hpp:1085:29: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
Fix warnings in segmentation/progressive_morphological_filter.hpp

> progressive_morphological_filter.hpp:116:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> progressive_morphological_filter.hpp:133:42: warning: comparison of integers of different signs: 'boost::int32_t' (aka 'int') and 'size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in segmentation/approximate_progressive_morphological_filter.hpp

> approximate_progressive_morphological_filter.hpp:139:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> approximate_progressive_morphological_filter.hpp:157:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> approximate_progressive_morphological_filter.hpp:238:42: warning: comparison of integers of different signs: 'boost::int32_t' (aka 'int') and 'size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in people/hog.cpp

> hog.cpp:342:30: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> hog.cpp:344:32: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> hog.cpp:346:34: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
Fix warnings in tools/compute_hausdorff.cpp

> compute_hausdorff.cpp:91:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
> compute_hausdorff.cpp:105:21: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in recognition/surface_normal_modality.h

> surface_normal_modality.h:735:40: warning: comparison of integers of different signs: 'size_t' (aka 'unsigned long') and 'const int' [-Wsign-compare]
> surface_normal_modality.h:737:42: warning: comparison of integers of different signs: 'size_t' (aka 'unsigned long') and 'const int' [-Wsign-compare]
> surface_normal_modality.h:950:40: warning: comparison of integers of different signs: 'size_t' (aka 'unsigned long') and 'const int' [-Wsign-compare]
> surface_normal_modality.h:952:42: warning: comparison of integers of different signs: 'size_t' (aka 'unsigned long') and 'const int' [-Wsign-compare]
Fix warnings in tools/lum.cpp

> lum.cpp:116:22: warning: comparison of integers of different signs: 'int' and 'typename SLAMGraph::vertices_size_type' (aka 'unsigned long') [-Wsign-compare]
> lum.cpp:123:20: warning: comparison of integers of different signs: 'int' and 'typename SLAMGraph::vertices_size_type' (aka 'unsigned long') [-Wsign-compare]
Fix warnings in people/ground_based_people_detection_app.hpp

> ground_based_people_detection_app.hpp:227:21: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> ground_based_people_detection_app.hpp:229:23: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> ground_based_people_detection_app.hpp:246:21: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> ground_based_people_detection_app.hpp:248:23: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> ground_based_people_detection_app.hpp:344:23: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> ground_based_people_detection_app.hpp:346:25: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
Fix warnings in people/height_map_2d.hpp

> height_map_2d.hpp:96:14: warning: comparison of integers of different signs: 'int' and 'unsigned long' [-Wsign-compare]
> height_map_2d.hpp:139:11: warning: comparison of integers of different signs: 'int' and 'unsigned long' [-Wsign-compare]
Fix warnings in people/person_classifier.hpp

> person_classifier.hpp:141:30: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> person_classifier.hpp:143:30: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> person_classifier.hpp:153:12: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> person_classifier.hpp:154:12: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> person_classifier.hpp:157:12: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> person_classifier.hpp:158:12: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> person_classifier.hpp:206:30: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> person_classifier.hpp:208:30: warning: comparison of integers of different signs: 'unsigned int' and 'int' [-Wsign-compare]
> person_classifier.hpp:246:26: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
> person_classifier.hpp:248:28: warning: comparison of integers of different signs: 'int' and 'uint32_t' (aka 'unsigned int') [-Wsign-compare]
Fix warnings in common/io.hpp

> io.hpp:406:25: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
> io.hpp:433:29: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
> io.hpp:476:27: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
Fix warnings in test/test_grabbers.cpp

> test_grabbers.cpp:415:23: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
> test_grabbers.cpp:417:25: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
> test_grabbers.cpp:487:23: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
> test_grabbers.cpp:489:25: warning: comparison of integers of different signs: 'int' and 'const uint32_t' (aka 'const unsigned int') [-Wsign-compare]
Fix warnings in octree/octree_pointcloud_changedetector.h

> octree_pointcloud_changedetector.h:101:33: warning: comparison of integers of different signs: 'size_t' (aka 'unsigned long') and 'const int' [-Wsign-compare]
Merge pull request #751 from taketwo/fix-warnings

Fix compiler warnings