Read new MercOpinions.xml format (#323)

Requires accompanying gameDir change.

MercOpinions.xml now only contains opinions that are not 0. A new tag with fields "id" and "modifier" are used instead of old ones that had 255 <Opinion%d> $value$ </Opinion%d> tags for all profiles.

Loading time of MercOpinions.xml went down from ~4.047 s to 0.011 s due to this change with default 1.13 VFS config.

A small cmd utility tool for converting existing MercOpinions.xml data into the new format is available at https://github.com/Asdow/JA2-ConvertXMLData/tree/master

Tactical/XML.cpp

@@ -0,0 +1,9 @@
+#include "XML.h"
+
+const XML_Char* GetAttribute(const XML_Char* name, const XML_Char** atts) {
+	for (const XML_Char** pIter = atts; *pIter != NULL; pIter++) {
+		const XML_Char* key = *pIter++;
+		if (strcmp(key, name) == 0) return *pIter;
+	}
+	return NULL;
+}