1) Set attribute self.dryrun depending on whether we are in dry-run mode.
2) Don't actually call hooks in --dry-run (just log what you would
invoke
3) Don't write out the mbnames file in --dry-run mode.
Repository, and Folder levels still need to be protected in dry-run mode
as of now.
Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>