Introduce uthash to the XML reader

All hashmaps have not yet been replaced by uthash, but a few of them
now use pure C-based hashmaps.

Author: sjoelund

SimulationRuntime/c/simulation/simulation_info_json.c

@@ -33,7 +33,6 @@
 #include <expat.h>
 #include <errno.h>
 #include <string.h>
-#include "util/uthash.h"
 #include <stdio.h>
 #include "util/rtclock.h"
 #include "util/omc_mmap.h"