FS-10036: update cJSON code to pre 1.4.0 release of cJSON.  this includes backports of all our fixes, and our build macros for windows and visibility.  It also makes it easy to drop in a new version, and to in the future be able to switch to a system version of cJSON easily (after all these updates are in, probably around v2.0 timeframe.  Note this new version adds a lot of extra error checking, fixes some buffer overruns, and improves parser and printer performance