New parse_string cJSON code from upstream.
New parse_string cJSON code from upstream.

Conflicts:

	src/http/json/cJSON.cc
Fix for a regression in our cJSON variant.
Fix for a regression in our cJSON variant.
Merge branch 'v1.12.x' into next
Merge branch 'next' of github.com:rethinkdb/rethinkdb into next
Merge branch 'next' into sam_2156