don't throw exception in getBearerToken if no token was passed
don't throw exception in getBearerToken if no token was passed

SergioEnrique/oauth2-php,danielfleck/oauth2-php,FriendsOfSymfony/oauth2-php,borNfreee/oauth2-php,McOffsky/oauth2-php,nnmer/oauth2-php,gencer/oauth2-php