junk files in hbn/ and possibly elsewhere

[yarikoptic]

(git)smaug:/mnt/btrfs/datasets/datalad/crawl/hbn[master]
$> /usr/bin/find */* -iname '._*' -o -iname '*.bak' | nl | tail
  4814	EEG/EEG/raw/mff_format/NDARZX561DR9/info1.xml.bak
  4815	EEG/EEG/raw/mff_format/NDARZX561DR9/._info1.xml.bak
  4816	EEG/EEG/raw/mff_format/NDARZX561DR9/._notes.xml
  4817	EEG/EEG/raw/mff_format/NDARZX561DR9/._sensorLayout.xml
  4818	EEG/EEG/raw/mff_format/NDARZX561DR9/sensorLayout.xml.bak
  4819	EEG/EEG/raw/mff_format/NDARZX561DR9/._sensorLayout.xml.bak
  4820	EEG/EEG/raw/mff_format/NDARZX561DR9/._signal1.bin
  4821	EEG/EEG/raw/mff_format/NDARZX561DR9/._subject.xml
  4822	EEG/EEG/raw/mff_format/NDARZX561DR9/Contents/._Info.plist
  4823	EEG/EEG/raw/mff_format/NDARZX561DR9/Contents/._PkgInfo

those files came from the tarballs