JSCBC-825: Fixed definition of search facets in queries.
JSCBC-825: Fixed definition of search facets in queries.

Motivation
----------
The facets for a SearchQuery are specified as a map of name
to the SearchFacet object, but the SDK exposed it as an array
of Facets instead.

Changes
-------
Changed 'facets' field on SearchQuery to be a map of string to
SearchFacet rather than an array of SearchFacet.

Change-Id: I106bf42f1c4b3601313a5c1b2cb91b585af44521
Reviewed-on: http://review.couchbase.org/c/couchnode/+/153053
Reviewed-by: David Kelly <d83cd2a93a916ce0b0d4c1349b44be044799feca@gmail.com>
Tested-by: Brett Lawson <c8c4369773d7d7226e031f0c4af62e3f38a08510@gmail.com>

brett19/couchnode,brett19/couchnode,couchbase/couchnode,couchbase/couchnode,brett19/couchnode,couchbase/couchnode,couchbase/couchnode