Fix multiple translations to work with --save-confidences

[benjaminking]

This PR addresses Issue #810, allowing multiple translations to work with confidence score calculations. Due to the extra parameters needed from the translator for calculating confidence scores, this involved a fair bit of refactoring.

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This change is 

[mshannon-sil]

@mshannon-sil reviewed 4 of 4 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @benjaminking)

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silnlp/common/translator.py line 277 at r1 (raw file):

            else:
                trg_draft_file_path = trg_file_path
            write_corpus(trg_draft_file_path, translated_draft.get_all_translations())

I might just be missing it, but I did a search of the repo in both the master and this branch, and I don't see a method corresponding to get_all_translations()

[benjaminking]

Reviewable status: 3 of 4 files reviewed, 1 unresolved discussion (waiting on @mshannon-sil)

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silnlp/common/translator.py line 277 at r1 (raw file):

Previously, mshannon-sil wrote…

I might just be missing it, but I did a search of the repo in both the master and this branch, and I don't see a method corresponding to get_all_translations()

Good catch! I had meant to rename a method and forgot to do that. I've fixed it and tested that it works with text file translation.