Move tests and bump to 2018 edition

Cargo.toml

@@ -2,6 +2,7 @@
 name = "humansize"
 version = "1.1.1"
 authors = ["Leopold Arkham <leopold.arkham@gmail.com>"]
+edition = "2018"
 
 description = "A configurable crate to easily represent file sizes in a human-readable format."
 

src/file_size_opts/defaults.rs

@@ -1,4 +1,4 @@
-use file_size_opts::{
+use crate::file_size_opts::{
   FileSizeOpts,
   Kilo,
   FixedAt,

src/lib.rs

@@ -15,7 +15,6 @@
 //! provided by the options module.
 //!
 //! ```rust
-//! extern crate humansize;
 //! use humansize::{FileSize, file_size_opts as options};
 //!
 //! fn main() {

tests/test.rs

@@ -1,5 +1,6 @@
-use humansize::{file_size_opts, FileSize};
+use humansize::{file_size_opts::{self, BINARY, DECIMAL, CONVENTIONAL}, FileSize};
 
+#[test]
 fn test_sizes() {
 
     assert_eq!(0.file_size(BINARY).unwrap(), "0 B");