Added ~Gradient() to free the pattern

src/gradient.cc

@@ -98,3 +98,11 @@ Gradient::Gradient(double x0, double y0, double r0, double x1, double y1, double
   _x0(x0), _y0(y0), _x1(x1), _y1(y1), _r0(r0), _r1(r1) {
   _pattern = cairo_pattern_create_radial(x0, y0, r0, x1, y1, r1);
 }
+
+/*
+ * Destroy the pattern.
+ */
+
+Gradient::~Gradient() {
+  cairo_pattern_destroy(_pattern);
+}

src/gradient.h

@@ -22,6 +22,7 @@ class Gradient: public node::ObjectWrap {
     inline cairo_pattern_t *getPattern(){ return _pattern; }
 
   private:
+    ~Gradient();
     double _x0, _y0, _x1, _y1, _r0, _r1;
     cairo_pattern_t *_pattern;
 };