software/resampling: add wrapper

src/software/resampling/extensions.rs

@@ -0,0 +1,10 @@
+use util::format;
+use ::{decoder, Error, ChannelLayout};
+use super::Context;
+
+impl decoder::Audio {
+	pub fn resampler(&self, format: format::Sample, channel_layout: ChannelLayout, rate: u32) -> Result<Context, Error> {
+		Context::get(self.format(), self.channel_layout(), self.rate(),
+		             format, channel_layout, rate)
+	}
+}