cjson: bump to version v1.0.2

cjson: bump to version v1.0.2

This is a major update in cjson:
 - project site moved from sourceforge to github
 - project recommends to use the new cmake buildsystem instead of the
   legacy make
 - BR2_STATIC_LIBS is now OK (README does not mention issue anymore)
 - As include path and library name have changed, tinycbor has to be
   updated
 - As cjson can now be built as a static library, fix a bug in
   json2cbor compilation from tinycbor package

Signed-off-by: Fabrice Fontaine <fabrice.fontaine@orange.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>