Bug fix: token validation failure

- When the JwtSecurityTokenHandler validates a token, it will have a
different behaviour wether you pass a token string or a
JwtSecurityToken. In the latter case, it will reencode the token instead
of using the initial one (RawData), which will have the side effect of
stripping out the CR/LF chars and thus produce a different signature!
- updated NuGet package System.IdentityModel.Tokens.Jwt to latest
version 3.0.2