Add EM350 PTT extended command support for RIL library.
change RIL_UNSOL_PTT_GROUP_INDICATOR_UPDATE's response from char ** to raw bytes
add PTT commands support in libril
define RIL_REQUEST_PTT_QUERY_BIZ_STATE in ril.h
remove RRRRIL_UNSOL_PTT_GROUP_INFO_CHANGED and RIL_UNSOL_PTT_CALL_GRANT_STATUS_CHANGED from ril.h