[libcvd-members] Problems with fast corner code

[Georg Klein]

This is with fast_corner_detect_10, but probably applies to others as 
well.

fast_corner_detect_10, when using faster_blah_10, crashes on images whose 
width is not a multiple of 16; this is because of the lines

        const byte* const end = I[I.size().y - 3]-16;
        for (const byte* p = I[3] + 16; p!=end; p+=16) {
                                        ^^^^

For images where size isn't a multiple of 16 but the check still works 
(e.g. width multiple of 8, even number of rows) the code doesn't crash, 
but produces spurious corners at the image edges.

Before the recent fast merge, this was not a problem since I was using 
slow FAST for the cases where this comes up. I don't understand the faster 
code enough to fix this myself, alas. What I could do is add checks to the 
logic which decides which detector to use, but I don't think that's the 
right way, no?