Explicitly export 5-8 formats

[jbosse]

Excel sheets that use formats 5-8 export the formatCodes for 5-8 because 5-8 are not standard values. Even though Excel can read a file without the formatCodes for cells using this numFmtId values other libraries may arise an exception when detecting format ids without an accompanying code.

This PR explicitly adds them to all files. I would have preferred to only include them if they were used but I punted since always including styles for 100 and 101 seem to have been included without issue.