Do not remove character at start of paragraph when cutting

Do not remove character at start of paragraph when cutting

The part of code that removed space at start of paragraph have been
there forever, but its intent is unclear. For example, cutting text at
the end of a paragraph will lead to remove space at the start of this
same paragraph.

The removal of this functionality is offset by a rewrite of DEPM that
makes it more thorough.

Fixes bug #10503.