Move puck finding workflow to separate function.

I also did many more things, like renaming variables and declaring Mat's as static variables within the function, but I really don't want to commit all that separately right now.

This code has not been tested.
Add parameters for board HSV filtering.
Change GUI to reflect refactor.
Add a spacer.
Update GUI code to propagate UI settings to ROS.
Implement most of the code necessary to recognize the board.

Vector clearing stopped working, however.
Fix bad drawing.
Add board_min_size field.
Read board_min_size field from GUI.
Add Mat for debug.
Rename input image for find_puck to hsv_image for clarity.
Merge branch 'master' of github.com:yoos/school