Release 3.4.1

Changes

• gui:
  • line style option
  • hex, bin adn physical display mode for integer channels
  • cursor, range, statistics
  • save and load channel statistics
  • see docs for complete functionality (http://asammdf.readthedocs.io/en/master/gui.html)
• update documentation for new demo example and GUI tool

Fixes

• lib: use logging with the logger name 'asammdf' (issue #63)
• lib: fix MDF3 error when chanining operations (cut.convert.resample)
• lib: fix cut when start is higher than the last timestamp
• fix for issue #66