allow public uses of structs; add sample program

src/image.rs

@@ -2,7 +2,7 @@ use crate::mock;
 
 #[derive(Debug, Eq, PartialEq)]
 pub struct Image {
-    pub(crate) pixels: Vec<u8>, // 64 for SD, 256 for HD
+    pub pixels: Vec<u32>, // 64 for SD, 256 for HD
 }
 
 impl From<String> for Image {
@@ -12,8 +12,8 @@ impl From<String> for Image {
         let pixels: Vec<&str> = string.split("").collect();
         // the above seems to add an extra "" at the start and end of the vec, so strip them below
         let pixels = &pixels[1..(pixels.len() - 1)];
-        let pixels: Vec<u8> = pixels.iter().map(|&pixel| {
-            pixel.parse::<u8>().unwrap()
+        let pixels: Vec<u32> = pixels.iter().map(|&pixel| {
+            pixel.parse::<u32>().unwrap()
         }).collect();
 
         Image { pixels }