Limit Guzzle dependency to version 5 or 6

v1.0.5

v1.0.4

• Allow testing by exposing interfaces
• Added .gitignore
• Added travis-ci config file

v1.0.3

Fixed: token variable was not set in Oauth2 Basic Auth constructor

v1.0.2

Compatibility with Guzzle 6.* (on top of 5.3)
Update CA bundle

v1.0.1

Fixed: missing Accept header in Oauth2 request
Merged: pull request #2 (PSR-2 coding style)

v1.0.0

First stable release.