* allout.el (allout-yank-processing): Fix injection of extra space between

* allout.el (allout-yank-processing): Fix injection of extra space between
bullet and non-whitespace character in first topic when pasting, ensuring
that the actual spacing in the pasted topic following the bullet char is
preserved.  This extra space was causing pasted encrypted topics to get a
decrypted status even when the content was actually still encrypted.  Now
the decryption status from before the paste is preserved.

(allout-flag-region): Set all allout overlays so they evaporate when
reduced to zero length (evanescent), to prevent overlay leakage.