add push src and flow combiner

gst/base/gst_push_src.go

@@ -0,0 +1,30 @@
+package base
+
+/*
+#include "gst.go.h"
+*/
+import "C"
+
+import (
+	"unsafe"
+
+	"github.com/tinyzimmer/go-gst/gst"
+)
+
+// GstPushSrc represents a GstBaseSrc.
+type GstPushSrc struct{ *GstBaseSrc }
+
+// ToGstPushSrc returns a GstPushSrc object for the given object.
+func ToGstPushSrc(obj *gst.Object) *GstPushSrc {
+	return &GstPushSrc{&GstBaseSrc{&gst.Element{Object: obj}}}
+}
+
+// wrapGstPushSrc wraps the given unsafe.Pointer in a GstPushSrc instance.
+func wrapGstPushSrc(obj *C.GstPushSrc) *GstPushSrc {
+	return &GstPushSrc{&GstBaseSrc{gst.FromGstElementUnsafe(unsafe.Pointer(obj))}}
+}
+
+// Instance returns the underlying C GstBaseSrc instance
+func (g *GstPushSrc) Instance() *C.GstPushSrc {
+	return C.toGstPushSrc(g.Unsafe())
+}