Added a ktica test that compares the linear ktica solution to the tica solution. This isn't perfect because the regularization in either case is being applied slightly differently. Maybe there's a better test to do here, but I haven't come up with it. Also, the same issue with multiprocessing on macs as we faced earlier is happening when I try to use multiple threads in the kernel calculation. I have set the n_jobs parameter to one, but maybe we can expose it.