Memset MCInst to 0 on initialization.

Old modules (and possibly the new ones as well) are not build for not initialized MCInst.
They assume it leads again and again to segfaults or false disassembly due to this.

MCInst.c

@@ -18,6 +18,7 @@
 
 void MCInst_Init(MCInst *inst, cs_arch arch)
 {
+	memset(inst, 0, sizeof(MCInst));
 	// unnecessary to initialize in loop . its expensive and inst->size should be honored
 	inst->Operands[0].Kind = kInvalid;
 	inst->Operands[0].ImmVal = 0;