inference in chain-structured factor graphs.

--HG--
rename : dlib/optimization/find_map_nmplp.h => dlib/optimization/find_max_factor_graph_nmplp.h
rename : dlib/optimization/find_map_nmplp_abstract.h => dlib/optimization/find_max_factor_graph_nmplp_abstract.h
rename : dlib/test/find_map_nmplp.cpp => dlib/test/find_max_factor_graph_nmplp.cpp

it begins randomly subsampling possible detection locations rather than
just stopping the detection procedure.

routines.

setting this value too low can sometimes result in the failure of the
structural_svm_object_detection_problem.

a tool for learning the parameters for an object like scan_image_pyramid.

way they should have been.

represented by an image scanner.

version of dlib.

routines so they return both the MSE and R-squared values rather than just the
MSE.

 - Changed the behavior of spatially_filter_image().  Now it won't truncate signed pixel values
   to 0 if they go negative.

as a matrix rather than C-array.  I also fixed a bug which showed up when using
non-square filters.  The bug would cause the edges of the output image to be incorrect.