Refactor fixup

[shenker]

Fixes https://github.com/tlambert03/nd2/issues/50

• Renamed fixup kwarg to validate_frames in _chunkmap.read_new_chunkmap.
• Set validate_frames to default to False.
• Renamed bad/fixed/safe to bad/fixed/good in read_chunkmap.
• Add validate_frames and search_window kwargs to ND2File.init to pass through to _util.get_reader -> _sdk/latest.ND2Reader.init -> _chunkmap.read_new_chunkmap.

@tlambert03 I'm running into horrible library path issues (probably related to https://github.com/tlambert03/nd2/issues/24) so I can't test this myself currently... I'm trying to fix things, will probably open another issue later today.

[tlambert03]

Thanks! I pushed some slight fixes directly to your branch (where the keyword "safe" was still being used)

[tlambert03]

@tlambert03 I'm running into horrible library path issues

can you tell me how you set up the environment? (I think you're one of the first to try)... we can dig into this in another issue though

[tlambert03]

all green! thanks a lot @shenker!