Miscellaneous patches to Earnings

[qmac]

Earnings21:

• Fix file 4341191 labels that are shifted off by one
• Resolves #35

Earnings22:

• Fixed casing label of numerics from UC/CA/LC to N/A
• Fixed preparation error that led to some files (~80) having atmospherics such as <crosstalk> or <inaudible> appear without <>. Now they should be easier to filter out/account for in evaluation. As a side effect, some words that were marked as guesses by the transcriber now appear as <unk>. For example line 1275 in file 4329526 Romero --> <unk>. We will try to patch this in the future.