Release 0.18.25

- read the bare KM3NET_TIMESLICE tree as the :TS stream, which holds the super
  frames the data filter discarded (JChecksum failures), complementary to
  L0/L1/L2/SN
- checksum() and isvalid() for super frames, a port of Jpp's JChecksum
  (PMT_ERROR, TDC_ERROR, TIME_ERROR, UDP_ERROR), reproducing it hit for hit
- DAQ status accessors (hrvstatus, fifostatus, hasudptrailer, ...) generalised
  to super frames via AbstractDAQFrame, plus testdaqstatus()
- eachtimeslice() and eachL0/L1/L2/SN/TStimeslice(), with a module_ids filter
- eachsummaryslice()
- timesorted keyword for eachevent(), eachsummaryslice() and eachtimeslice(),
  with the permutation derived from the header branches alone and cached
- object-wise streamed super frame collections are now read as well
- renamed hasl0timeslices -> hasL0timeslices (likewise L1, L2, SN) and added
  hasTStimeslices