NOTE: This can change the assembly slightly, in my case it reordered two
instructions. This is due to the change from:

    which = (10 * which) + *pointer++ - '0';

to

    which = (10 * which) + (*pointer++ - '0');

This means that after the change, the subtraction runs before the
addition instead of after that. That shouldn't change the behavior
though.

Add const qualifiers

Functions like cJSON_Print do not and should not modify the object passed
to them.

Reformatting code