Fix compiler warnings

All are harmless but for the sake of clarity have
fixed them all bar a couple;

- Lucene grumbles about signed/unsigned conversion which
  is/isn't valid depending upon the version of CLucene you
  compile with. Either way it is harmless.

- QxtScheduleView has a bunch of issues, but since it is a
  third party widget its better to leave it unchanged.

src/DataFilter.cpp

@@ -254,9 +254,9 @@ bool Leaf::eval(DataFilter *df, Leaf *leaf, SummaryMetrics m)
 
     case Leaf::Operation : 
     {
-        double lhsdouble, rhsdouble;
+        double lhsdouble=0.00, rhsdouble=0.00;
         QString lhsstring, rhsstring;
-        bool lhsisNumber, rhsisNumber;
+        bool lhsisNumber=false, rhsisNumber=false;
 
         // GET LHS VALUE
         switch (leaf->lvalue.l->type) {