Added hasAccessToken to the storage interface. Reordered the storage functions to match the interface.
Fixed PHPRedis hasaccesstoken implementation
Cache tokens in PHPRedis
Adding clearToken to storage adapters
Adding clearToken to all providers and unit tests.
Merge branch 'master' of https://github.com/TheSavior/PHPoAuthLib into TheSavior-master

Conflicts:
	src/OAuth/Common/Storage/Memory.php
	src/OAuth/Common/Storage/PHPRedis.php
	src/OAuth/Common/Storage/Session.php
	src/OAuth/Common/Storage/SymfonySession.php
	src/OAuth/Common/Storage/TokenStorageInterface.php
Merge branch 'master' of https://github.com/Lusitanian/PHPoAuthLib