make us robust against missing TLE files

tle.cc

@@ -102,6 +102,8 @@ TLERepo::Match TLERepo::getBestMatch(time_t now, double x, double y, double z, T
       continue;
     }
   }
+  if(distances.empty())
+    return TLERepo::Match();
   if(secondbest) {
     auto iter = distances.begin();
     if(iter != distances.end()) {

tle.hh

@@ -16,14 +16,14 @@ public:
     std::string name;
     int norad;
     std::string internat;
-    double inclination; // radians
+    double inclination{360}; // radians
     double ran;         // radians
-    double e;       
-    double ecefX;  // m
-    double ecefY;  // m
-    double ecefZ;  // m
+    double e{-1};       
+    double ecefX{0};  // m
+    double ecefY{0};  // m
+    double ecefZ{0};  // m
 
-    double eciX, eciY, eciZ; // m
+    double eciX{0}, eciY{0}, eciZ{0}; // m
     double distance{-1}; // m
 
     double latitude, longitude, altitude;