Add "Save all files with <eol> EOL characters" option

[dougthor42]

There should be an option on the editor to always save files with LF / CRLF / CR line endings.

Basically this would run Source -> Convert end-of-line characters on every save. There might be a more sophisticated or faster way to do it, but I'm not aware of one.

Option screen could look like:

I'll open a PR for this to see how you guys like it. Defaults will be the status-quo: EOLs are not changed on save.

(Edit1: replaced text representation of option screen with image)

[ccordoba12]

I like it. Thanks a lot @dougthor42 for taking a look at it!