Write RawNumber without quotes

[h46incon]

This PR try to fix issue that Writer.RawNumber() writes number as string with quotes (#560 #704 #852). Some Considerations:

1. Raw number should contain characters in range [1,127], so it's safe that cast it to OutputStream::Ch.
2. No futher checking as WriteRawValue().

[coveralls]

Coverage increased (+0.0002%) to 99.919% when pulling a5648d4 on h46incon:FixWriteRawNumber into 83f149e on Tencent:master.

[coveralls]

Coverage increased (+0.0002%) to 99.919% when pulling a346863 on h46incon:FixWriteRawNumber into 83f149e on Tencent:master.

[h46incon]

@miloyip The encoding is more complex than I thought, like #1179.

[chrisvroberts]

Hi @miloyip, @h46incon.

I am trying to understand why this has been closed. looking at master HEAD RawNumber in writer.h still calls WriteString meaning quotes will be added to numbers. This breaks the whole idea of the SAX reader and the writer having the same interface because the JSON output by RawNumber in the writer won't match the input read in by the reader and presented in the RawNumber call back.

1234 -> SAX reader -> RawNumber -> "1234"
"1234" -> RawNumber -> writer ->"\"1234\""

Can RawNumber(p, l, b) not just call RawValue(p, l, kNumberType)?

[pitrou]

Indeed the behaviour of RawNumber is unexpected and is also biting us.
If the concern is to avoid breaking compatibility, perhaps add a boolean flag for the desired behaviour?