only constants in escape() method, unicode cache, clean up of possibly unnecessary code https://github.com/salyh/fleece_tmp/commit/a8d852bc3beeddc9607af1005a2cfdde2f252230
long is integral https://github.com/salyh/fleece_tmp/commit/03dc2df406d171ded8db5199d4618786d29e5298 Thanks Hendrik
