added date validation dedicated exception

[Spyna]

for issue #153

[hzalaz]

Thanks for the PR @Spyna can you try to reduce the diff the PR has, e.g. avoid reordering the class elements since its hard to tell what you changed?

[Spyna]

@hzalaz I' ve restored the original order.
The modified method is assertValidDateClaim

[lbalmaceda]

Hi @Spyna
Thanks for the changes. We think it should throw a specific Exception only in case the exp claim is invalid: lets call that TokenExpiredException and make it extend JWTVerificationException, as it's not that the claim it's invalid but rather that the token was ok but it has expired. Also let's keep the InvalidClaimException in case of invalid nbf and iat claims. Sounds good to you?

The changes should be done in the assertValidDateClaim method: When the boolean is true means we are here for the exp claim, and if it's invalid we should throw this new exception type. When the boolean is false, means it's one of the other two claims and if it's invalid we should throw the old exception. You can also split the method in 2 and handle these scenarios in a separate way if you want. Please make sure to add/update the tests to check the new exception.

Cheers

[Spyna]

Sounds great to me,
I'll modify the code and push,

thank you

[lbalmaceda]

@Spyna Please rollback the code formatting changes in order to leave a clearer diff of the JWTVerifier class. Besides that it's looking fine. Thanks