clarified spec
Clarified the error message a user gets when they try to load a jpeg or png file
but didn't link to the approrpiate library.
Fixed spelling error in spec
Fixed grammar
Added a length_squared() member to vector.
Added distance_to_line() and clip_line_to_rectangle()
Added hough_transform
Added hough transform unit tests
updated docs
Added example of accessing individual pixels
Added an example program for the new hough_transform object.
updated docs
Added an example for svm_c_trainer.
updated docs
Changed code to avoid a warning