Inconsistent token_type values 'bearer' and 'Bearer'

[bambeusz]

Problem:
There is inconsistency in token type value. In header name Bearer is required, but while creating access token bearer is used by default. This leads to problem described here:
FriendsOfSymfony/FOSOAuthServerBundle#180

class OAuth2\OAuth2 line 181:

    const TOKEN_BEARER_HEADER_NAME = 'Bearer';

class OAuth2\Oauth2 line 259:

    const TOKEN_TYPE_BEARER = 'bearer';

Suggestion:
change default value of TOKEN_TYPE_BEARER field to Bearer

[themizzi]

+1