pack: Add format specifiers s#, + and +#
Replace strcpy with memcpy

Since len is known, the copy function does not need to check byte by byte
the end of the string.

Signed-off-by: Olivier Langlois <olivier@olivierlanglois.net>
Merge pull request #134 from lano1106/master

Replace strcpy with memcpy
Clarified json_load_callback_t return value docs
Mention success first in json_load_callback_t docs
Mention success first in json_load_callback_t docs
Merge branch '2.4'
Clarified json_load_callback_t return value docs
Mention success first in json_load_callback_t docs
Merge branch '2.4'
doc: Fix index type for json_array_foreach()
jansson 2.5
Add versionadded to the new json_pack() format specifiers
Support \u0000 - add size_t string lengths to API, load and dump \u000, etc.
Also:
  Steal strings during parsing for half the mallocs!
  Change all input-caused assertions to errors.  No crashes please, we're programmers.
dump \u sequences as upper case for readability (just like error messages)
expect "export" in test configs
document new null-friendly functions
Merge pull request #140 from chipdude/nuls

Support "\u0000" in strings
add new public functions to jansson.def
Merge pull request #141 from chipdude/nuls

add new public functions to jansson.def