Move number format tests into dedicated module.

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branch : 1.8
Allow comparison of number formats both with each other and also with simple strings.

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branch : 1.8
Separate object representation from the hash function. Seeing as the hash is actually hashed you the repr is useless anyway.

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branch : 1.8
Make all hashables comparable.

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branch : 1.8
Whitespace

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branch : 1.8
Check for class or value equality.
Set FILL_NINE = None; hope this won’t break anything in Excel
Fix some failing tests for conditional formatting.

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branch : 1.8