On Windows, when run `npm run lint`, a **LOT** of the following errors
appeared:
```
 error  Expected linebreaks to be 'LF' but found 'CRLF'  linebreak-style
```

This error only occurs on Windows because the `linebreak-style` eslint
setting was set to "unix". This is fixed by making the eslint config
file a Javascript script and setting the platform based on the build
platform.

Thus, the `linebreak-style` will be "windows" or "unix" depending on the
users platform.

Add .gitattributes that will convert line endings automatically to LF when uploading to GitHub

Include lint check for line endings

Restore eslint linebreak style check for unix since LF line endings will be enforced

This was necessary because git was showing that the CRLF line endings were being converted to LF for PNG files on Windows