worked on wifi-scanner for linux

new time-grouping for vap grouper
adjusted test-cases
minor changes/fixes/improvements

sensors/radio/AccessPoint.h

@@ -58,6 +58,13 @@ public:
 	/** OPTIONAL: get the AP's ssid (if any) */
 	inline const std::string& getSSID() const {return ssid;}
 
+	/** as string for debuging */
+	std::string asString() const {
+		std::string res = "AP(" + mac.asString();
+		if (!ssid.empty()) {res += ", '" + ssid + "'";}
+		res += ")";
+		return res;
+	}
 
 };