Update gitignore
Add OpenCV's original camshiftdemo.cpp
Added local movie playback support

Without argument it uses the camera (as before)
With an argument plays that file.
Playback starts paused on the first frame, press p to play.
Code reformatting
Add original Spline.hpp

Source: http://shiftedbits.org/2011/01/30/cubic-spline-interpolation/
License: Beerware
Spline.hpp code reformatting
Add integer-pixel based spline interpolation and statistics
Refactor stats code into Stats.hpp

Also, use sub-pixel precision float coordinates