completed rename. merged crates to features

src/main.rs

@@ -1,7 +1,7 @@
-use canvas::Canvas;
-use color::Color;
-use structs::Tuple;
-use matrix::Matrix;
+use features::canvas::Canvas;
+use features::color::Color;
+use features::structs::Tuple;
+use features::matrix::Matrix;
 
 use std::fmt;
 use std::fs::File;