signature dashes show be followed by a space

[wjcarpenter]

LogicMail uses the de facto convention of putting two dashes on a line above the signature. The actual convention, however, is DASH DASH SPACE (a space follows the dashes). Various pieces of software recognize that 3-character sequence as the beginning of the signature. Most (properly) do not recognize just DASH DASH.

(Observed in a recent 1.9 download.)

[octo]

I did not know that convention, but since its trivial to fix, I'll accept this one for 1.1 and 2.0