[ldolse]

It was something I saw that was done during markdown conversion (and liked it) but markdown conversion only applies to txt. I figured the appropriate place to make that sort of change was if the user enabled the smarten_punctuation checkbox.

In a similar vein the same checkin also converts ellipsis which are three dots - '. . .' or '...' - to the ellipsis entity, as another user had complained about ebook renderers wrapping lines in the middle of an ellipsis.

Both would probably make sense in the actual smartypants library, but since I don't maintain that library I didn't stick it there, it's just in Calibre's code. Other tweaks can be done easily, as Kovid noted.

Edit - I didn't read the second half of your request til after I wrote the part about the ellipsis - anyway, a happy coincidence.