Complete cell-SAM with two channel selection

[mimithecoconut]

Can select two main channels to connect to cell-SAM and generate masks.

[rossbar]

@mimithecoconut I went ahead and pushed up reversions of the windows line endings that were extraneously added due to a bad editor config at some point. It looks like it was only affecting old files so hopefully the updated configuration makes this a non-problem moving forward; it might be worth double-checking your editor configuration though!