pkg: add jsmn minimal JSON parser

[kaspar030]

From https://github.com/zserge/jsmn:

"Jsmn is a world fastest JSON parser/tokenizer."

edit

The supplied test application is a basically unmodified copy of jsmn's examples/simple.c. I've just added the license, fixed main's prototype, lowered the token number to adapt to RIOT's little stack and run uncrustify over it.

[OlegHahm]

"a world fastest"? lol

[cgundogan]

nice! works perfectly on master, however I don't get output when trying on an samr21-xpro

[Kijewski]

"a world fastest"

I saw a project a few days ago that claimed to be the fastest JSON tokenizer by eating anything that roughly resembles JSON. :) E.g.

{
    "answer": 42,
    "key"   true_but_actually_only_the_leading_t_is_checked;
    "number" -111.hm.not.really
    fALSE "actually, why should keys be strings?"
]

[kaspar030]

however I don't get output when trying on an samr21-xpro

Huh, just tried, works like a charm here. Need to press the reboot button after "make flash term" as the output comes very fast.

[cgundogan]

Need to press the reboot button after "make flash term" as the output comes very fast.

I forget this every time..

[kaspar030]

@cgundogan was that an ACK? :)

[cgundogan]

nope, will test again now.

[cgundogan]

Works like charm! ACK

[kaspar030]

Thanks for reviewing! &go.