Add form feed and vertical tab whitespace to isWhiteSpace()

[jamesgiu]

Ran into an issue with these characters not being detected and having false positive isBase64() detection as a result - would be good to get them counted as whitespace.

Ref. C/C++ isspace() function considers these characters as whitespace. http://www.cplusplus.com/reference/cctype/isspace/ https://www.oreilly.com/library/view/c-in-a/0596006977/re129.html

Cheers!

[coveralls]

Coverage remained the same at 94.308% when pulling 90248547061e7708c6e2e2807e60feacfcb12680 on jamesgiu:VT-and-FF-in-BNCodec into 475910a521bd23dbba26091be505ad2a71d3e901 on apache:master.

[jamesgiu]

Hi all, any chance this will be looked at? Cheers :)

[garydgregory]

This method or PR is not great because we are defining our own whitespace instead of reusing Charater.isWhitespace or Charater.isSpaceChar.

Shouldn't we be using Charater.isSomething?

[garydgregory]

Ping. Also, how does this square with the RFCs for Base64, Base32, and Base16 (all the subclasses we implement)? IOW, what C/C++ does is completely irrelevant, it's the RFCs that matter.