Logbook file open/close changes

Fixed seg fault opening invalid or empty logbook file
Changed to allow saving an empty adif logbook file

src/logbook/adif_io.cxx

@@ -1,5 +1,7 @@
 #include <FL/Fl.H>
 #include <FL/filename.H>
+#include <FL/fl_ask.H>
+
 
 #include "adif_io.h"
 #include "config.h"
@@ -118,7 +120,12 @@ void cAdifIO::readFile (const char *fname, cQsoDb *db) {
     fread (buff, filesize, 1, adiFile);
     fclose (adiFile);
     
-    char *p1 = buff, *p2;
+    if (filesize == 0 || (strstr( buff, "<ADIF_VERS:")) == 0) {
+    	fl_message("Not an ADIF log file");
+    	return;
+	}
+
+	char *p1 = buff, *p2;
 // is there a header?
     if (*p1 != '<') { // yes find the start of the records
         p1 = strchr(buff, '<');

src/logbook/logsupport.cxx

@@ -130,10 +130,11 @@ void cb_mnuOpenLogbook(Fl_Menu_* m, void* d)
 }
 
 void cb_mnuSaveLogbook(Fl_Menu_*m, void* d) {
-	if (qsodb.nbrRecs() == 0) return;
 	const char* p = FSEL::saveas("Save logbook file", "ADIF\t*." ADIF_SUFFIX,
 				     logbook_filename.c_str());
 	if (p) {
+		logbook_filename = p;
+		dlgLogbook->label(fl_filename_name(logbook_filename.c_str()));
 		if (adifFile.writeLog (p, &qsodb))
 			fl_message ("Could not write to %s", p);
 		qsodb.isdirty(0);