* refactor check_pr_approval, allow using github login-id

2. remove the tricks for paddle.fluid.layers.ops.func

* add testcases

* simplify the test data, and added to file diff approvals

* remove a approver

* test_print_signatrues runs on a simple pipeline, no paddle installed

* testcases for print_signatrures and sampcd . python3 only.

* remove unused import directives

* remove unused import directives

* test

* test

* test2

* wip

* test using pr id

* test

* add log

* add log

* test

* test

* test

* test

* add approver check

* revert travis ci

* merge latest api.spec

* fix get token

* update API.spec

* up to date