Fixed #254 - LoTW QSL import reports unmatched QSOs sometime

QLog has a time tolerance of +-1 hour for QSL import (eQSL and LoTW).
However, if there is the same QSO in this +-1 hour interval, QLog declares
this QSO as Unmatched, because it is not able to pair them exactly
(even though they have the same times).

It seems that LoTW time tolerance is +-30 minutes. Qlog is changed
to the same interval.

logformat/LogFormat.cpp

@@ -252,7 +252,7 @@ unsigned long LogFormat::runImport(QTextStream& importLogStream,
                             "WHERE callsign=upper(:callsign) "
                             "AND upper(mode)=upper(:mode) "
                             "AND upper(band)=upper(:band) "
-                            "AND ABS(JULIANDAY(start_time)-JULIANDAY(datetime(:startdate)))*24<1") )
+                            "AND ABS(JULIANDAY(start_time)-JULIANDAY(datetime(:startdate)))*24*60<30") )
     {
         qWarning() << "cannot prepare Dup statement";
         return 0;
@@ -589,7 +589,7 @@ void LogFormat::runQSLImport(QSLFrom fromService)
         }
 
         // It is important to use callsign index here
-        QString matchFilter = QString("callsign=upper('%1') AND upper(mode)=upper('%2') AND upper(band)=upper('%3') AND ABS(JULIANDAY(start_time)-JULIANDAY(datetime('%4')))*24<1")
+        QString matchFilter = QString("callsign=upper('%1') AND upper(mode)=upper('%2') AND upper(band)=upper('%3') AND ABS(JULIANDAY(start_time)-JULIANDAY(datetime('%4')))*24*60<30")
                 .arg(QSLRecord.value("callsign").toString(),
                      QSLRecord.value("mode").toString(),
                      QSLRecord.value("band").toString(),