Triku

- Change adata.uns['triku'] standard from """ to "None" for compatibility purposes with anndata h5 savng.

- Change adata.uns['triku'] standard from None to "" for compatibility purposes with anndata h5 savng.

- Added doc fixes and corrected standard pipeline.

- Minor fix in convolution. probability array is applied np.close instear of array of convolution.

- Fixed nan or inf distances for spurious zero-count genes.
- Added option to correct distances using mean or median (by default is median).

- Fixed error in knn_array calculation for "conn"