Add ability to classify many candidates from the ratings page

[PaulHancock]

• The ability to select candidates in a particular radius or in a particular observation (or both) and apply the same classification to all would reduce the number of times the user encounters false positives with the same cause. I picture a check box next to each candidate in the "nearby candidates" list under the diagnostic plot which when clicked, mirrors the classification from the currently viewed candidate.

• There should also be a list for candidates in the same observation as the currently viewed candidate, with the ability to classify all candidates in a whole observation, similar to nearby candidates above

[PaulHancock]

This is now possible as of f79644955e2486f154d027a70b70394d02298e98

The nearby candidates table has check-boxes that users can select, and the rating/comment will also be applied to these candidates.

There is a check box in the "observation" section that will apply the given rating/comment to all candidates that belong to that observation.

The observation takes precedence over the nearby candidates. If needed I can make it so that it is the union of these two that are applied.