updates

* redesigned experiments
* rewritten evolution cost matrix from scratch (getcost_contigevolution)
-> runs in linear time
-> now works by modifying cosine matrix in place like the contig version
-> takes a new parameter, the order of differences
* optimizations in get_cosinematrix
-> optionally uses GPU if show.use_gpu
-> caches the fft result using a persistent variable
-> if more than fft_limit samples per dft, will use the fixed
resample_matrix.m to save computation