remove obsolete "extern crate" syntax

README.md

@@ -36,7 +36,6 @@ for use in your own Rust applications. can both parse and export Bitsy game data
 a simple example program:
 
 ```rust
-extern crate bitsy_parser;
 use bitsy_parser::game::Game;
 use std::{env, fs};
 

src/bin/bitsy-dedupe.rs

@@ -1,4 +1,3 @@
-extern crate bitsy_parser;
 use bitsy_parser::game::Game;
 use std::{env, fs};
 

src/bin/bitsy-merge.rs

@@ -1,4 +1,3 @@
-extern crate bitsy_parser;
 use bitsy_parser::game::Game;
 use std::{env, fs};
 

src/bin/bitsy-parse.rs

@@ -1,4 +1,3 @@
-extern crate bitsy_parser;
 use bitsy_parser::game::Game;
 use std::{env, fs};
 

src/bin/bitsy-validate.rs

@@ -1,4 +1,3 @@
-extern crate bitsy_parser;
 use bitsy_parser::game::Game;
 use std::{env, fs};