basic start to using Elastic search as the cache layer
Moved the cache into its own module
Fetch items not in the local cache from elastic search
Simplify the filter logic for uncached items
Extended the API class to include updating the cache as a private method. Now requires users to pass in the key for elastic search
Updated tests
Moved elasticSearch functionality into it's own method. Preserve existing functionality
You can now use mget with a single id as a string
Merge branch 'v3' into v3-elastic-search-cache

Conflicts:
	README.md
	lib/api.js
	lib/v1/items.js
	lib/v1/requestHandler.js
Updated to reflect the new mget method
Bumped the version
Merge pull request #74 from Financial-Times/v3-elastic-search-cache

V3 elastic search cache, adding a new method to fetch multiple items in a single request
Merge branch 'v3' of https://github.com/Financial-Times/ft-api-client into error-statuses

* 'v3' of https://github.com/Financial-Times/ft-api-client:
  Bumped the version
  Updated to reflect the new mget method
  You can now use mget with a single id as a string
  Updated tests
  Extended the API class to include updating the cache as a private method. Now requires users to pass in the key for elastic search
  Simplify the filter logic for uncached items
  Fetch items not in the local cache from elastic search
  Moved the cache into its own module
  basic start to using Elastic search as the cache layer

Conflicts:
	lib/v1/items.js
	test/apiSpec.js