checked in first bits of code for cache service data optimisation,

distrib can build grps xml document
added pugixml src code into utilities

pls see design document:
http://retroshare.sourceforge.net/wiki/index.php/Documentation:design_services_histories

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@4076 b45a01b8-16f6-495d-af2f-9b41ad6348cc

libretroshare/src/dbase/cachestrapper.cc

@@ -259,6 +259,21 @@ bool	CacheStore::getStoredCache(CacheData &data)
 	return ok;
 }
 
+bool CacheStore::cached(const std::string cacheId)
+{
+
+	return false;
+}
+
+void CacheStore::updateCacheDocument(pugi::xml_document& cacheDoc)
+{
+	return;
+}
+
+void CacheStore::updateCacheTable()
+{
+	return;
+}
 
 bool	CacheStore::locked_getStoredCache(CacheData &data)
 {