* new node: GuessNiceBlockSize.
* new feature: image quilting nodes get a special block size range that uses guess_nice_block_size; also works with parallel batch but the guess must be done before parallelization in order to setup the total number of steps in pbar.
* fixes: node options using shallow copy fixed; fixed parallelization error when lookup is None; fixed edge case in bse_desc_util.py.
* misc: guess_nice_block_size can be given an alternative upper bound (needed when patching H seam); guess_nice_block_size can run bse_ft only for faster analysis.
* checks sift descriptors sizes.
* checks distances between above mentioned descriptors.
* checks freq. w/ high magnitude in ft.
* selects a size that is close to a multiple of the distances obtained in above listed analyses.
Bruno Madeira