[feature]Qiu: add environment object

environment object could return environment information.
[feature]Qiu: add sinon package in

will use sinon in node mocha unit testing
[feature]Qiu: db config according to environment

environment().db.connection could return the current development/test/production's db connection string
according to the process.env.NODE_ENV argument, by default it's set to development
[feature]Qiu: use database configuration while running app
[feature]Qiu: add grunt-env in project and fix testcase

because we could link to different db as per the environent,
so add grunt-env in and use env:development represent development environment.

some db connection string in testcases are static, already updated using environment()
Merge pull request #19 from twers/environment-db-configurable

Environment db configurable