dummyhub bugfix: dummydb save failed due to pickle circular import
fix regtest: move faketime forward to 2000, eliminate noise from output, recreate refs
added regtest/README
regtest README: added overview and better explained how/why to recreate refs
restore bugfix: don't move files to rollback if they don't exist in the overlay

rational: duplicity doesn't backup sockets so they don't exist in the overlay,
but TKLBAM doesn't take this into account, so the end result is the deletion of
sockets (and any other filetype that is ignored by duplicity)
backup bugfix: register socket into fsdelta as a status path, not an overwrite

rational:

- duplicity doesn't backup unix sockets, so there's nothing in the overlay to
  overwrite with.

- even if duplicity did backup unix sockets we still wouldn't want to overwrite
  them. They don't have any content.
tklbam-restore usage bugfix: --l => --limits
Merge remote branch 'liraz/master'