To do after merging new hash table memory layout

[marcelm]

After merging #278, a couple of things need to be done. I’ll add them here as individual bullet points. We can convert anything that is not super easy to do into separate issues.

• [x] Update baseline commit
• [x] Update changelog
• [x] "Time estimating number of unique hashes" message is now incorrect
• [x] Add accessors for RefRandstrobeWithHash
• [x] Rename RefRandstrobeWithHash to RefRandstrobe since we no longer need a RefRandstrobe without hash
• [x] Add one or two comments describing the memory layout
• [x] Add error handling when invalid bits/-b values are provided
• [x] Some refactoring so that nam.cpp doesn’t need to know the memory layout of the index
• [x] #304
• [x] Remove leftover get_count_line_search declaration

[marcelm]

Closing this issue and moving the last to-do item into a separate one.