LilyPond versions paths: why not just asking for one path (where all binaries are located)?

[fedelibre]

When we want to add a version of LilyPond in the Preferences, we are asked to enter three paths (lilypond, convert-ly and lilypond-book). These must be full paths, at least if you have multiple versions or binaries located in directory not in the $PATH variable.

Since all these commands are located in the same directory, it would be easier (and less error-prone) if we were asked just for the path to the binaries for that version. Something like:

~/bin
/usr/bin
~/lilypond-git/out/bin

Then Fresco would use the lilypond, convert-ly and lilypond-book binaries located in that directory.

[wbsoft]

you only have to use a full path to the lilypond binary. the others simple need a filename, if they are in the same dir.

(I should document this somewhere)