[disjoint] add alternative (more robust) implementation of segment-box disjointness test; the alternative implementation does not use any divisions
[test][length] do not test the variant-related code if GEOMETRY_TEST_DEBUG is defined
(the variant-related code does not compile when GEOMETRY_TEST_DEBUG is defined)
[test][perimeter] do not test the variant-related code if GEOMETRY_TEST_DEBUG is defined
(the variant-related code does not compile when GEOMETRY_TEST_DEBUG is defined);
replace bg::perimeter_result (non-existing) by bg::default_lentgh_result (error
produced when compiling with -DGEOMETRY_TEST_DEBUG)
[doc] Added Samuel and fixed some doc issues for distance
[get_turns][relate][test][index] Fix unused variable warnings.

In the rtree/pack_create replace (void)variable to boost::ignore_unused_variable_warning().
[extensions][dissolve] repaired dissolve w.r.t. turn changes
[extensions][dissolve] added extra unit tests for cw/ccw check
[overlay][relate][within][test] Fix unused variable warnings.
[index/example] Add the visualization of knn Box/Box and Seg/Box to glut_vis example
[doc][example] Update the knn queries section in docs. Improve knn query visualization in glut_vis.
[doc] Fix quickref.xml to support new parameter name of nearest(). Also improve the knn examples info.
[distance] fix bug in point-box distance computation in range-to-segment/box code
[index][example] Improve the rtree visualization.

Add support for rtrees storing Points and Segments.
Add the support for Segments in print_indexable() and gl_draw_indexable() index utilities.
[doc] Add info about Segments Indexables and more pictures.
[doc/index] Updated example rtree pack creation time, after optimization.
[doc/index] Compact the new knn query pictures. Add knn code snippet.
[test][distance L/A] add two seg-box test cases provided by Adam Wulkiewicz
[test][distance] in the case of the segment-box combination,
also test output with respect to the generic algorithm that first
checks for intersection, and if that fails, checks all possible
point-segment combinations of the segment and and the box
[distance] modify the point-to-range code so that a container/range
of points can be passed as an argument (e.g., a vector of points)
[distance] modify the range-to-segment/box code, so that in the case
of computing the distance of a point of the range from the box, the
point-to-range code in point_in_geometry.hpp is used