- avoid Use of uninitialized value $target_base warnings as realpath
  may return undef.  For example:
  $ perl -wle 'use Cwd qw(realpath); my $rp = realpath(shift); print "rp($rp)";' "/my/path has/space"
Use of uninitialized value $rp in concatenation (.) or string at -e line 1.
rp()
- anchor regex for vim swap files to start with a period/dot(.)
- add regexs to skip emacs .#* temporary files and backup (ending in ~)