Merge pull request googleapis#842 from google/issue-821 removes auth library caching

Merge pull request googleapis#816 from gws/configurable-curl-proxy-wo… …rkaround Make cURL proxy header calculation bug workaround configurable

Merge pull request googleapis#768 from google/add-support-for-guzzle-6 Add support for guzzle 6

force 0.4 for google-auth 

Merge pull request googleapis#695 from bshaffer/v2-rcb-1 v2.0 RCB-1

makes new tests for verifyIdToken php-53-array friendly 

Merge pull request googleapis#677 from bshaffer/issue-669 fix googleapis#669 - update Bigquery for UDF

Merge pull request googleapis#563 from google/ianbarber-patch-1 Bump dev version string.

Merge pull request googleapis#548 from woofyman99/master More efficient file upload from URL