Add long value support

Some APIs like Telegram Bot API return responses with values that cannot be accepted with simple valueint. parse_number() function doesn't actually accept numbers larger than INT_MAX/INT_MIN - if the number is one of those (i.e larger than INT_MAX - integer overflow), the result of "item->valueint" will be INT_MAX. In case overflow, let it try storing the value anyways.

cJSON.h

@@ -115,6 +115,7 @@ typedef struct cJSON
     char *valuestring;
     /* writing to valueint is DEPRECATED, use cJSON_SetNumberValue instead */
     int valueint;
+    long valuelong;
     /* The item's number, if type==cJSON_Number */
     double valuedouble;