Native EC Key Generator and AES GCM dependency updated (Spomky-Labs#151)

* AES GCM algs updated and ECKey Generator modified

Private keys from APN support (Spomky-Labs#146)

* Bug fixed and test added
* PKCS#8 key loader added
* Applied fixes from StyleCI

JKU and X5U key sets added (Spomky-Labs#144)

* JKU and X5U key sets added
* Documentation updated

Update JWKFactoryInterface.php

Storable JWKSet (Spomky-Labs#126)

* Storable and Rotatable JWKSet added
* Tests added
* Documentation updated

use=>sig added for all none keys created by the factory

Minimum requirement updated

Examples fixed

Merge branch 'master' of https://github.com/Spomky-Labs/jose

PHPSecLib removed and Support for RSA key without all primes added (S…

…pomky-Labs#115)