Update drizzlepac notebooks to account for new DQ 'bits' definitions

[mackjenn]

3 notebooks have outdated parameter values:

https://github.com/spacetelescope/notebooks/blob/master/notebooks/DrizzlePac/align_to_catalogs/align_to_catalogs.ipynb

driz_sep_bits,final_bits='64, 32' should be '64, 16'

https://github.com/spacetelescope/notebooks/blob/master/notebooks/DrizzlePac/sky_matching/sky_matching.ipynb

final_bits='64' should be '16'

https://github.com/spacetelescope/notebooks/blob/master/notebooks/DrizzlePac/optimize_image_sampling/optimize_image_sampling.ipynb

driz_sep_bits,final_bits='64,512' should be '16,512'

[catherine-martlin]

See PR #127 for current progress