Version upgrade 0.1.0 to 0.2.0

Main functionality corrections

• Fixed incoherence between the sorting order of the list of explored models and their performance
  statistic, stored at the xm@log.success@sols and xm@log.success@fitness slots of the Xfgpm
  object delivered by fgpm_factory(). Now the models in xm@log.success@sols are correctly
  sorted in decreasing order by performance.

• Resolved bug causing crash in fgpm_factory() during structural optimization with only functional
  inputs, e.g., for the call fgpm_factory(fIn = fIn, sOut = sOut). Thanks to Jérémy Rohmer for
  pointing out the bug.

• Resolved bug causing crash in fgpm_factory() during structural optimization with only scalar
  inputs, e.g., for the call fgpm_factory(sIn = sIn, sOut = sOut).

Minor display changes

• Iproved display of progress bars for fgpm() and fgpm_factory()

• Improved placing of the legend in plotX() to prevent hiding important information

Minor flow changes

• format4pred() deprecated for get_active_in()