physioex 2.0.4

Data-layer fixes found by an audit of what physioex reads against the raw files of every dataset. Label caches of
Sleep-EDF, WSC and Alzheimers are recomputed on first use (LABELS_REVISION 2, 2 and 3). Cached WSC events are not
versioned: delete events/<subject>.json of the 26 allscore nights whose events changed.

Fixed

• WSC .allscore.txt: labels and events are anchored at START RECORDING. A STAGE - NO STAGE line timed before it
  moved the time origin back by hours and shifted every later label (45 of 743 files). Midnight is a backward jump of
  the clock, PAUSED to RECORDING RESUMED stretches are removed (the EDF has no samples there), and labels or events
  past the end of the EDF are dropped. A file without START RECORDING yields no labels, as before.
• Sleep-EDF: the hypnogram always runs to 24 h; its tail is cut at the end of the PSG instead of being paired with
  zero padding (in one night 614 epochs of Wake).
• Alzheimers: labels past the end of a truncated EDF are dropped.
• MESA: *_Off electrode-status flags (1 Hz) are classified OTHER, not EEG/EOG/EMG.

Added

• WSC events from .sco.txt (the 1827 Gamma-system nights; only the 743 Twin-system .allscore.txt nights had
  events). Same event types as the allscore parser. Scan # x2 counts samples at twice the EDF rate; a few files write
  the scan with two extra digits (the clock column is used) and 548 write the length ×100 with a negative sign.