proper stripping of sigs on reply:
proper stripping of sigs on reply:

 o only allow for '--' if clearsigned, '-- ' otherwise
 o strip last occurance of '-- ' in msg, not first
 o strip sig before quoting to avoid unecessary work

svn path=/trunk/kdenetwork/kmail/; revision=151129

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi