created new package with a lib for linear clustering

- The linear clustering algorithms that I've developed, are not used anymore in my project, so, in order to mantain them if they will be useful again later, I'll put them in a separate project.
- The linear clustering algorithms needs some modifications in order to be really "Linear" and not to depend on the width of the image, I'm not going to do this yet...
- Eliminated all the references to Linear Clustering Algorithms in the c_vision code