adds vendor directory

vendors dependencies in standard `vendor` directory, managed by glide

vendor/github.com/mattn/go-gtk/example/sourceview/sourceview.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"github.com/mattn/go-gtk/gtk"
+	gsv "github.com/mattn/go-gtk/gtksourceview"
+	"os"
+)
+
+func main() {
+	gtk.Init(&os.Args)
+	window := gtk.NewWindow(gtk.WINDOW_TOPLEVEL)
+	window.SetTitle("SourceView")
+	window.Connect("destroy", gtk.MainQuit)
+
+	swin := gtk.NewScrolledWindow(nil, nil)
+	swin.SetPolicy(gtk.POLICY_AUTOMATIC, gtk.POLICY_AUTOMATIC)
+	swin.SetShadowType(gtk.SHADOW_IN)
+	sourcebuffer := gsv.NewSourceBufferWithLanguage(gsv.SourceLanguageManagerGetDefault().GetLanguage("cpp"))
+	sourceview := gsv.NewSourceViewWithBuffer(sourcebuffer)
+
+	var start gtk.TextIter
+	sourcebuffer.GetStartIter(&start)
+	sourcebuffer.BeginNotUndoableAction()
+	sourcebuffer.Insert(&start, `#include <iostream>
+template<class T>
+struct foo_base {
+  T operator+(T const &rhs) const {
+    T tmp(static_cast<T const &>(*this));
+    tmp += rhs;
+    return tmp;
+  }
+};
+
+class foo : public foo_base<foo> {
+private:
+  int v;
+public:
+  foo(int v) : v(v) {}
+  foo &operator+=(foo const &rhs){
+    this->v += rhs.v;
+    return *this;
+  }
+  operator int() { return v; }
+};
+
+int main(void) {
+  foo a(1), b(2);
+  a += b;
+  std::cout << (int)a << std::endl;
+}
+`)
+	sourcebuffer.EndNotUndoableAction()
+
+	swin.Add(sourceview)
+
+	window.Add(swin)
+	window.SetSizeRequest(400, 300)
+	window.ShowAll()
+
+	gtk.Main()
+}