Fix bugs

• add sha256 encryption support for signature (thx: jbackman)
• fit for latest ansible(v2.8.6) and ansible-runner(v1.4.2)
• add more error event capture in response

More lightly web-framework

use sanic as web-framework and keep ansible-runner as middleware, avert hang status sometimes

using ansible-runner as middleware

ansible-runner and NOT use ansible code immediately. No need to fit every ansible version and more stable for complex task.

v0.2.6 fit for ansible 2.6.x

shell, playbook mode tested pass, setup tested pass

fit for ansible 2.3.x

v0.2.2

remove code about authkeys