As of now, the parameter is unused, but may be needed in the future.
I'm adding it now so that in the future both API and ABI remain
backwards compatible as long as possible.
This is a backwards incompatible change.
Replace all occurences of unsigned int and unsigned long with size_t.
This is a backwards incompatible change, as the signature of many API
functions changes.
With this encoding flag, the object key-value pairs in output are in
the same order in which they were first inserted into the object.
To make this possible, a key of an object is now a serial number plus
a string. An object keeps an increasing counter which is used to
assign serial number to the keys. Hashing, comparison and public API
functions were changed to act only on the string part, i.e. the serial
number is ignored everywhere else but in the encoder, where it's used
to order object keys if JSON_PRESERVE_ORDER flag is used.
