Bug 1021714 part 1 - Eliminate "goto syntax" in date_parseString. r=njn

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extra : rebase_source : 7a5d30ad5346e8b06e04cad82f0637ad5ee7dfbf
Bug 1021714 part 2 - Move some variable declarations. r=njn

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extra : rebase_source : 74dde3ee49f8397f6d6ef6b7bc0851d0bcea643f
Bug 1021714 part 3 - More date_parseString cleanup. r=njn

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extra : rebase_source : 18254fb8d0296c82ad7ca1fd79166fbbaeda1fc0
Bug 1021714 part 4 - Some date_parseISOString cleanup. r=njn

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extra : rebase_source : 4ab27793d02767c461305d43aa4863c06fbf14c9
Bug 1021714 part 5 - More date parsing cleanup and handle Latin1 strings. r=njn

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extra : rebase_source : 441b2756563065546a24ef1723a78a5a5c032aac