Add note of defeat re: includes to compile

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/compile.rs

@@ -39,6 +39,7 @@ impl<'s> Compile<'s> {
     }
 
     fn parse_include(&mut self, _path: &str) -> Vec<SpStmt> {
+        // Includes are a tough nut to crack. Come back to this later.
         todo!("includes")
     }