NURBS fitting: fixed trimming curve for surface fitting (parameter was wrong)
Cleaned up code in B-spline fitting example;
Added tutorial for trimmed B-spline fitting
added saving of trimmed bsplines, added viewer for trimmed bsplines, added saving of bspline in bspline fitting tutorial
Bspline tutorial: reviewed tutorial and added it to the index
Merge pull request #518 from tmoerwald/master

Tutorial "Fitting trimmed B-splines to unordered point clouds"
Merge branch 'master' of https://github.com/PointCloudLibrary/pcl