v3.6.2

Release fixing number of substantial bugs.

Main bugs fixed:

• #768 Restored erroneously deleted sqw/dnd methods
  eplicate and sqw method
  un_inspector. Added unit tests for these methods.
• #771 Fixed the issue, causing inability to set up instrument and sample on large old version filebased sqw files, as the algorithm
  was trying to load all pixel data in memory
• #780 Fixed Tobyfit not working on recently generated sqw files. The Tobyfit was assuming that all pixel indexes run numbers are
  enumerated from 1 to the number of data headers, while in fact recent sqw files contain actual run number.
• #781 Fixed bug in spaghetti plot. The routine was failing.
• #782 Complex synchronization bug has been fixed in combine_sqw.mex code. For some types of pixel data it was causing
  loss of combined pixels and incorrect sqw file as the result.
• #785 Cuts on large old versioned sqw files were extremely slow, as pixel_range was recalculated each time