add bitsy-parse executable for independent testing of import/export

src/bin/bitsy-parse.rs

@@ -0,0 +1,15 @@
+extern crate bitsy_parser;
+use bitsy_parser::game::Game;
+use std::{env, fs};
+
+const SYNTAX_ERROR: &str = "Usage: `bitsy-parse input.bitsy output.bitsy`";
+
+/// simply parses and re-exports a game. use to test whether output matches input.
+fn main() {
+    let input  = env::args().nth(1).expect(SYNTAX_ERROR);
+    let output = env::args().nth(2).expect(SYNTAX_ERROR);
+
+    let game = Game::from(fs::read_to_string(input).unwrap()).unwrap();
+
+    fs::write(output, game.to_string()).expect("Failed to write output file");
+}