Switch the crate to Rust edition '2018'

Cargo.toml

@@ -1,6 +1,7 @@
 [package]
 name = "ruduino"
 version = "0.1.1"
+edition = "2018"
 authors = [
   "The AVR-Rust Project Developers",
   "Jake Goulding <jake.goulding@gmail.com>",

core_generator/build.rs

@@ -91,8 +91,7 @@ fn generate_cores_mod_rs(mcus: &[Mcu]) -> Result<(), io::Error> {
 fn write_core_module(mcu: &Mcu, w: &mut dyn Write) -> Result<(), io::Error> {
     writeln!(w, "//! Core for {}.", mcu.device.name)?;
     writeln!(w)?;
-    writeln!(w, "use {{RegisterBits, Register}};")?;
-    writeln!(w, "use modules;")?;
+    writeln!(w, "use crate::{{modules, RegisterBits, Register}};")?;
     writeln!(w)?;
 
     gen::write_registers(mcu, w)?;

core_generator/gen.rs

@@ -48,7 +48,7 @@ pub fn write_pins(mcu: &Mcu, w: &mut dyn Write) -> Result<(), io::Error> {
     if let Some(port) = mcu.peripheral("PORT") {
         writeln!(w, "pub mod port {{")?;
         writeln!(w, "    use super::*;")?;
-        writeln!(w, "    use Pin;")?;
+        writeln!(w, "    use crate::Pin;")?;
         writeln!(w)?;
 
         for instance in port.instances.iter() {

src/modules/spi/clock.rs

@@ -1,4 +1,4 @@
-use config;
+use crate::config;
 
 /// A clock mask.
 ///

src/modules/spi/mod.rs

@@ -4,7 +4,7 @@ mod clock;
 // FIXME: Start using this module or delete!!!
 #[allow(dead_code)] mod settings;
 
-use {Register, Pin};
+use crate::{Register, Pin};
 
 /// An SPI module.
 ///

src/modules/timer/timer16.rs

@@ -1,4 +1,4 @@
-use {RegisterBits, Register};
+use crate::{RegisterBits, Register};
 use core::marker;
 
 /// A 16-bit timer.

src/modules/timer/timer8.rs

@@ -1,4 +1,4 @@
-use {RegisterBits, Register};
+use crate::{RegisterBits, Register};
 use core::marker;
 
 /// A 8-bit timer.

src/modules/usart.rs

@@ -1,4 +1,4 @@
-use Register;
+use crate::Register;
 
 pub trait HardwareUsart {
     /// The USART data register.

src/pin.rs

@@ -1,4 +1,4 @@
-use Register;
+use crate::Register;
 
 /// Represents whether a pin is an input or an output.
 pub enum DataDirection {

src/prelude.rs

@@ -1,4 +1,4 @@
 //! Re-exports commonly-used APIs that can be imported at once.
 
-pub use interrupt::without_interrupts;
+pub use crate::interrupt::without_interrupts;