Tried corner detection, cursor capture

Used very simple SSD based corner detection, found it to be lacking and
very slow. Tried to implement cursor capture of window in background but
forcing window to be in foreground seems to be necessary for the cursor
capture to work. Added code to draw circles to help with visualizing
when points are selected. Code is in a bit of a mess as I've franticly
tried these two things, but will likely revert back these changes and go
forward with an alternate route.