We don't need to copy the entire printbuffer, only the part that is
used.

This allowed for the removal of a lot of if (p) checks.

This restructures parse_string in a way, that you need to keep less
state in your head to understand the code.

This is achieved by:
* only changing the input pointer (current position) at a few places
(not all throughout)
* splitting out the UTF16 handling into a separate function
* renaming the variables so you know what they do without additional
context

This only attaches the parsed linked lists to the items passed to
parse_object and parse_array.

This replaces the bit fiddling involved with calculating a new buffer
size by just multiplying the required length by two, paving the way to a
complete switch to size_t at a later point in time.

Introduces a preprocessor directive that aborts the compilation if the
version numbers in the header don't match with the numbers in the c
file.

This sets the type of an item only if parsing was successful.

This means that in case of failure, the item's type will remain to be
cJSON_Invalid.

This fixes a double free that happens when calling cJSON_Delete on an
item that has been used by parse_string and it failed parsing the
string.

The double free happens, because parse_string frees an alias of
item->valuestring, but doesn't set item->valuestring to NULL.

This might cause slight changes in behavior, but it shouldn't break
anything that is not already broken (for example the original macro
could either return a double, or an integer or whatever depending on if
object is NULL or not.)

Replaces the hand written floating point parser with the C library
implementation.

Simplify error handling using goto fail and improve some names.

Makes the control flow easier to reason about and fixes a few potential
memory leaks.

Makes the control flow easier to reason about and fixes a few potential
memory leaks.

Makes the control flow easier to reason about and fixes a few potential
memory leaks.

Introducing the switch defaults in an earlier commit made UTF-16 \u
sequence handling broken.

Makes type conversions explicit, if they alter a value

If the number is bigger or smaller than the biggest or smallest integer,
the behavior would be undefined.

This commit defines it as saturation behavior.