Performance

[owensd]

Number parsing performance is ok:

NSJONSerialization:
performance results: min: 10.716ms, max: 17.004ms, avg: 11.802ms

JSONLib:
performance results: min: 7.801ms, max: 20.115ms, avg: 8.418ms

From this file: https://github.com/chadaustin/sajson/blob/master/testdata/mesh.json

String parsing performance is terrible:

NSJONSerialization:
performance results: min: 4.687ms, max: 9.183ms, avg: 5.242ms

JSONLib:
performance results: min: 24.347ms, max: 36.947ms, avg: 26.928ms

From this file: https://github.com/chadaustin/sajson/blob/master/testdata/twitter.json

In addition to having an arbitrary depth limit, some of this needs to be revisited.