SUGGEST: add_field, validate_indices undefined fix

This cleans up some old leftovers.
SUGGEST: add completion-type suggestion

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-suggesters-completion.html
SUGGEST: improvements to Suggest object

Add type so that the .add function doesn't perform strange autodiscovery.
Instead, provide the developer with a uniform API for adding suggestions.
Merge pull request #435 from CGenie/suggest-fixes

Suggest fixes