Closes GH-20.

Replace them with jsonp_malloc() and jsonp_free() to support the
custom memory allocation.

The keys which are stored temporarily to a hashtable to make sure that
all object keys are unpacked, were hashed with the object key hashing
function. It is meant to compute hashes for object_key_t values, and
it works incorrectly for plain strings.

Fixed by introducing suitable functions for hashing and comparing
strings for string-keyed hashtables.

* Use "printf" instead of "echo -n" as it's more portable
* Treat a test as skipped if it exits with exit status of 77
* Skip the check_exports test if "nm -D" doesn't work

Closes GH-17.

Return 0 as documented if the argument is not a JSON object.

Closes GH-18.

va_copy() is a C99 feature. In C89 implementations, it's sometimes
available as __va_copy(). If not, memcpy() should do the trick.

While at it, add -Wdeclaration-after-statement to AM_CFLAGS to catch
these in the future.

Closes GH-16.

It seems that the only way to do this is to use the dvi make target,
as it's built in make distcheck after running configure.

- Capitalize section titles correctly

- Rename "Building on Windows" to "Building on non-Unix systems" and
  tweak the text accordingly.

- Remove the "Installing Prebuilt Binaries" section. This info is
  better in the web instead, as it may change.

- Mention that Sphinx 1.0 or newer is required.

Wow, lots of stuff. And it's been a long while after the last release.

Closes GH-12.

json_error_t is used in the decoder and in the pack and unpack API's,
so it's better to have a separate section for it.

It's more helpful to see "...bar/baz.json" instead of "/long/path/to".

- Add a new field position to the json_error_t structure. This is the
  position in bytes from the beginning of the input.

- Keep track of line, column and input position in the stream level.
  Previously, only line was tracked, and it was in the lexer level, so
  this info was not available for UTF-8 decoding errors.

- While at it, refactor tests so that no separate "stripped" tests are
  required. json_process is now able to strip whitespace from its
  input, and the "valid" and "invalid" test suites now use this to
  test both non-stripped and stripped input.

Closes GH-9.

Thanks to Basile Starynkevitch for the suggestion and initial patch.
Thanks to Jonathan Landis and Deron Meranda for showing how this can
be utilized for implementing secure memory operations.

Functions taking va_args are munged to receive arguments of type
'__va_list_tag *'. This patch uses va_copy to coerce them to the expected type
so we don't get compiler errors.

Tested on x86_64, both 32-bit and 64-bit compiles.

Reported-By: Basile Starynkevitch <basile@starynkevitch.net>

Now, by default, unpacking doesn't check that all array and object
items are accessed. The check can be enabled globally by using the
JSON_STRICT flag (formerly JSON_UNPACK_ONLY), or on a per-value basis
by using the new '!' format character. The '*' format character is
still available to disable the global check on a per-value basis.

The "haiku" theme doesn't show chapter contents in sidebar.

Give the type name instead of its enum index in the error message when
an unexpected value is encountered while unpacking.

Expand the pack/unpack API: json_(un)pack is the simple version with
no error output, json_(un)pack_ex has error output and flags,
json_v(un)pack_ex is a va_list version of json_(un)pack_ex.

Implement unpacking flags:

- JSON_UNPACK_ONLY turns off extra validation, i.e. array and object
  unpacking doesn't check that all items are unpacked. This is really
  just convenience for not adding '*' after each object and array.

- JSON_VALIDATE_ONLY turns off unpacking, i.e. no varargs are expected
  and nothing is unpacked.

* By default, json_unpack() now checks that all items of arrays and
  objects are unpacked. This is useful for validation.

* Add format specifier '*' to suppress this check for individual
  arrays and objects. '*' must appear as the last format specifier
  before the closing ']' or '}'.

* Use the format string scanner from the previous commit (with the
  simpler separator skipping semantics)

* Split json_vnunpack() to three separate functions for unpacking
  objects, arrays and "simple" values

* Always return 0 on success, 1 on error

This shaves around 100 more lines from the original implementation.