Fix #1: Implementing the cache for the Deployment API.

This commit implements the requirements described in the Issue #1.

*	new file:   lib/deployment_cache.js
- Adding the library that deals with the caches
- The methods to load the cache, verify if the cache is stale,
  remove, and getting the cache location are provided.

*	modified:   lib/utils.js
- Couple of refactoring, Removing single quotes
- Adding methods to save Json, Open Json (not using require)
- Creating, deleting files, etc. added.

*	modified:   package.json
- Adding a new dependency to the timezone library.

*	modified:   src/deployments.js
- Adding the library for verifying the cache for the given deployment.

*	new file:   test/deployment_cache.js
- Adding the tests for the caching.
- Needs to run node.