Review of squashed/cleaned-up frequency-rt-4 branch

@Mona77 I've "squashed" your commits into a single commit, which makes it simpler to review.  I've also cleaned it up a bit by removing all modified files from this commit that didn't directly relate to your work (e.g., where whitespace was changed in a file, and that was the only change).

Can you please take a look at this, check it out and run it, and make sure everything still works as planned?

If so, I'll give you a few final steps to perform where you can create this same commit under your username and submit it as a pull request to the main OTP project.