Remove unused functions and declared functions?

[Vulpine05]

This question was brought up by @davidpanderson in (#5841 (comment)) that if a function is not used anywhere, it should be removed. I have found a few other functions that are declared in the header file with no inline code, and the function is not in the .cpp file.

I can create a PR to remove any unused function declarations that I have found, but I wanted to double check that this is okay to do. I didn't dig through the history of the code to see why there is a header with no code.

[davidpanderson]

Yes, please!