Add extra models to ledmodes

- Configurable anime example
- Gfx power states as enum

Closes #72

rog-anime/src/error.rs

@@ -0,0 +1,37 @@
+use std::error::Error;
+use std::fmt;
+use png_pong::decode::Error as PngError;
+
+#[derive(Debug)]
+pub enum AnimeError {
+    NoFrames,
+    Io(std::io::Error),
+    Png(PngError),
+    Format
+}
+
+impl fmt::Display for AnimeError {
+    // This trait requires `fmt` with this exact signature.
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            AnimeError::NoFrames => write!(f, "No frames in PNG"),
+            AnimeError::Io(e) => write!(f, "Could not open: {}", e),
+            AnimeError::Png(e) => write!(f, "PNG error: {}", e),
+            AnimeError::Format => write!(f, "PNG file is not 8bit greyscale"),
+        }
+    }
+}
+
+impl Error for AnimeError {}
+
+impl From<std::io::Error> for AnimeError {
+    fn from(err: std::io::Error) -> Self {
+        AnimeError::Io(err)
+    }
+}
+
+impl From<PngError> for AnimeError {
+    fn from(err: PngError) -> Self {
+        AnimeError::Png(err)
+    }
+}