pull in upstream interface improvements and add a few more gstreamer interfaces

examples/plugins/boilerplate/boilerplate.go

@@ -0,0 +1,27 @@
+//go:generate gst-plugin-gen
+//
+// +plugin:Name=boilerplate
+// +plugin:Description=My plugin written in go
+// +plugin:Version=v0.0.1
+// +plugin:License=gst.LicenseLGPL
+// +plugin:Source=go-gst
+// +plugin:Package=examples
+// +plugin:Origin=https://github.com/tinyzimmer/go-gst
+// +plugin:ReleaseDate=2021-01-18
+//
+// +element:Name=myelement
+// +element:Rank=gst.RankNone
+// +element:Impl=myelement
+// +element:Subclass=gst.ExtendsElement
+//
+package main
+
+import "github.com/tinyzimmer/go-glib/glib"
+
+func main() {}
+
+type myelement struct{}
+
+func (g *myelement) New() glib.GoObjectSubclass { return &myelement{} }
+
+func (g *myelement) ClassInit(klass *glib.ObjectClass) {}