Added checks to make sure the specified track exists

Added precondition checks to validate input files and paths to return more informative error messages as per #2

node_modules/detect-newline/readme.md

@@ -0,0 +1,42 @@
+# detect-newline [![Build Status](https://travis-ci.org/sindresorhus/detect-newline.svg?branch=master)](https://travis-ci.org/sindresorhus/detect-newline)
+
+> Detect the dominant newline character of a string
+
+
+## Install
+
+```
+$ npm install --save detect-newline
+```
+
+
+## Usage
+
+```js
+const detectNewline = require('detect-newline');
+
+detectNewline('foo\nbar\nbaz\r\n');
+//=> '\n'
+```
+
+
+## API
+
+### detectNewline(input)
+
+Returns detected newline or `null` when no newline character is found.
+
+### detectNewline.graceful(input)
+
+Returns detected newline or `\n` when no newline character is found.
+
+
+## Related
+
+- [detect-newline-cli](https://github.com/sindresorhus/detect-newline-cli) - CLI for this module
+- [detect-indent](https://github.com/sindresorhus/detect-indent) - Detect the indentation of code
+
+
+## License
+
+MIT © [Sindre Sorhus](http://sindresorhus.com)