Update 0 2

• documentation
  • api
  • update documentation
  • increase pymca widget documentation
  • check htmlhelp from orange-canvas
• pymca / larch compatibility chi == EXAFSSignal
• propose a different display for stack of curves (median / quartils ?)
• check TODOs
• link kweight widget with larch xftf, reset pymca kweigh parameter also ?
• check icons are installed with pip install [full]
• check to one 'strange' error with sqlite3 / larch thread id
• add an 'manual' update mode from gui