allow inlining (this did not provide a statistically significant performance boost - oh well)

src/colour.rs

@@ -6,6 +6,7 @@ pub struct Colour {
 }
 
 impl From<String> for Colour {
+    #[inline]
     fn from(string: String) -> Colour {
         let values: Vec<&str> = string.split(',').collect();