handle \u inside json parser

[olikraus]

Issue this pull request references: #477

Changes proposed in this pull request

• Handle the \u escape inside the json string parser

[RobLoach]

Is this something that could be pushed forwards to SimpleJSON ?

[olikraus]

Is this something that could be pushed forwards to SimpleJSON ?

Yes the same problem is here also:
https://github.com/nbsdx/SimpleJSON/blob/master/json.hpp#L528

Indeed the conformance report already revealed the problem (section 3, second test):
nbsdx/SimpleJSON#5

So by transfering this pull request to SimpleJSON, the expectation is, that the second test of the string conformance test will succeed.