adds logic discussed in https://github.com/bshaffer/oauth2-server-php/pull/275#issuecomment-30712851, adds tests from @weierophinney
ensures config values are propogated to HttpBasic and ClientCredentials for new 'allow_public_clients' config value
updates comment typo
allows for null client_secret from getClientCredentials function (as discussed in https://github.com/bshaffer/oauth2-server-php/pull/277/files#diff-756f723f587f0504239170eff6eaade8R40)
merges develop changes
changes 'expire' to 'delete'
renames skipped message to 'Skipped Storage', since it can be for more than one
removes mock redis client
Merge pull request #277 from bshaffer/address-257-allow-client_id-in-post-body-for-user-credentials-grant

adds logic discussed in #275
fixes composer command for travis
adds redis-server to services in travis.ci
Merge pull request #279 from bshaffer/addresses-258-predis-wrong-number-of-arguments

Addresses 258 predis wrong number of arguments
Allowing to set Postgresql as storage.
- PDOException with message SQLSTATE[42703]: Undefined column: 7 ERROR:  column "default" does not exist
Update AccessTokenInterface.php

addresses #238 - adds "user_id" as an optional param in the `getAccessToken` documentation
ensures PHP warnings do not get thrown as a result of an invalid argument to
Merge pull request #280 from bshaffer/jwt-php-warnings

ensures PHP warnings do not get thrown as a result of an invalid argument to $jwt->decode()
Update composer.json

addresses #283 - updates required version to `php 5.3.9`
addresses #286 - adds documentation and links to spec for not including error messages when no token is supplied, and when more than one method is used
changed response header from 200 to 401 when empty token received
Merge pull request #285 from n1te1337/fix-1

changed response header from 200 to 401 when empty token received