replace cjson with json-c

* Call json_object_object_foreach only inside own  block
  Otherwise it fails with couple errors like this:
  In file included from sysroots/qemux86/usr/include/cjson/linkhash.h:16:0,
  |                  from sysroots/qemux86/usr/include/cjson/json.h:22,
  |                  from Src/base/Security.h:31,
  |                  from Src/base/SystemService.cpp:50:
  | Src/base/SystemService.cpp:3626:2: error:   crosses initialization of
    'lh_entry* entry_nextkey'
  |   json_object_object_foreach(root, key, val)
  |   ^
  | Src/base/SystemService.cpp: In function 'bool cbEnableTouchPlot(LSHandle*,
    LSMessage*, void*)':
  | Src/base/SystemService.cpp:3717:1: warning: jump to label 'Done'
    [-fpermissive]
  |  Done:
  |  ^
  | Src/base/SystemService.cpp:3698:8: warning:   from here [-fpermissive]
  |    goto Done;
  |         ^
Merge pull request #12 from shr-project/webOS-ports/master

replace cjson with json-c