updates

* sped up sum/contig by not doing the double sum on calculation
* cosine matrix now not calculated completely, rather 10 overlapping
segments are calculated down the diagonal, yielding a significant cost
saving especially on T=1,2,...,5
* all of the discrete Fourier transform, normalization and convolution
is now vectorised
* show can be passed as an argument to execute_show to save time loading
it, when parameter searching
* FFT, convolution and dot products now computed on the GPU. A big
speed-up but now fails in the context of a parallel for loop which makes
it practically useless -- so we might need to forget about this.
* cosines should be and are on [-1,1]
* resample_vector matrix-ified, but apparently not working yet
Revert "updates"

This reverts commit 3b469a16610366feba3660a348b362bc6c40002c.
Revert "Revert "updates""

This reverts commit 32bfcf4f8c3176ce45efb62805a2840fb255b23d.