[NODEJS-1753] ACS Node SDK Rework Integration

## Ticket Information
***JIRA Ticket***
https://jira.appcelerator.org/browse/NODEJS-1749
https://jira.appcelerator.org/browse/NODEJS-1753

***Description***
This PR is about to introduce new ACS Node SDK implementation (acs-node-sdk 1.0.0-beta) redesigned via https://jira.appcelerator.org/browse/NODEJS-1598 and https://wiki.appcelerator.org/display/cls/Redesign+and+rework+of+acs-node-sdk.

We redesigned ACS Node SDK to support modern NodeJS features, and fixed existing issues of current ACS Node SDK like cannot support multiple instances. We also make it more flexible to add/update corresponding ACS API easily by using a generic way.
Moreover, we introduced travis and mocha test to make our ACS Node SDK unit-test driven, and avoid most potential code problem by JSHint code check.

For further and detailed information, please refer to README.md, examples and test cases within this PR.


## Suggested Test Steps
\- Create an ACS app and get its app key
\- Git clone this code
\- $ cd acs-node-sdk; export ACS_APPKEY=YOUR_CREATED_ACS_APP_KEY; npm test
some comments here would be very helpful