No source in es

DO NOT MERGE. I'm creating this for review purposes.

Changes to prevent us from storing source document or source fields in ElasticSearch
See also: https://issues.apache.org/jira/browse/USERGRID-255
Once a mapping is created for a type you can only add to it [1].  In UG2 we use a default mapping template so that all types get the same mappings. When a new type is created, e.g. when a new UG collection is added, ES will create a mapping for it based on the default mapping template. Once that happens, we cannot change the things specified by the mapping.

That means that, once an type is created the only way to change from "store source" to "do not store source" is to, for each type, delete the old mapping, create the new mapping and then re-index all data of the type.

I think I should delete the migration code I have written so far for this and instead, check our re-build index logic to make sure it deletes mappings for each type before it re-indexes the type.

[1] From ElasticSearch: The Definitive Guide, p. 93 in section "Updating a Mapping"