Added forced GC after each test.
Disable --trace-gc.
Fix segfault when Feature destructor decrements reference counter to 0.
Reproduced by: defn = new FeatureDefn(); feature = new Feature(defn); feature = null; gc(); feature = new Feature(defn);
Trigger appveyor.
Added support for GPX files (#60).
Merge branch 'refs/heads/gpx' into 0.2.x

* refs/heads/gpx:
  Added support for GPX files (#60).
  Trigger appveyor.
  Fix segfault when Feature destructor decrements reference counter to 0. Reproduced by: defn = new FeatureDefn(); feature = new Feature(defn); feature = null; gc(); feature = new Feature(defn);
  Disable --trace-gc.
  Added forced GC after each test.