- handle escaped escape characters (good catch by Maxime Martineau, thou...

...gh original posted fix is incomplete -- see example/test JSON file)

- speedup: copy chunks of input JSON at once instead of character-by-character when we can be sure those characters don't include important ones such as string delimiters or escape characters.

- example/test JSON + PHP page: added tests for escape series

- example/test JSON: added more nastiness to test: input whitespace, etc. handling


BTW: thanks for the previous merge!