Transcriptions with false negatives should not be graded

[KatieProchilo]

Here is an example of an utterance that is a false negative:

• expectedTranscription: "all right that's one milkshake"
• actualTranscription: "all right that's one milk_shake"

The important pieces of this utterance have clearly been picked up correctly by the speech service, but grading as it currently stands doesn't take into account these "false negatives."

Each transcription object should have something similar to a falseNegative field. Responses that are false negatives should not be taken into account when grading.