I believe the LUA editor is what it is.
While not perfect, here's what I do:

1. In LUA editor CTL-A CTL-C.
. This copies the text into the windows clipboard.
2. Open a wordpad document and CTL-V.
. This pastes the document into wordpad and resolved
. End-Of-Line issues.
3. In wordpad CTL-A CTL-C.
. This copies the document back into the clipboard
. with End-Of-Line resolved for notepad.
4. Open a notpad document and CT-V.
. I have the status enabled so I get line and character
. information at the bottom right. I can use CTL-G to
. get to a particular line.

Normally I work from a saved notepad copy of the script then
replace the entire document in the LUA editor but from time
to time I will make a bunch of changes in LUA. When I do I
repeat the above process. To get from Notepad to LUA editor
I do this:

1. In LUA editor CTL-A CTL-X
. This clears the script.
2. In Notepad CTL-A CTL-C
. This copies the script into the clipboard.
3. In LUA editor CTL-V
. This pastes the document into LUA from the clipboard.

I`m using external editor: n++
It can be set (and i`m doing it in my new updates) to "eol conversion" as "unix" and covert all /t to 4 spaces.
This way i remove X bobxes.
n++ have numbered lines :)

Like rav3n_pl, I also recommend using n++ because of the possibility to remove/replace garbage text.

A bump.
Maybe it is possible to merge n++ or some gnu editor to foldit client?