use wxversion.select(), not wxversion.ensureMinimal()

If wxversion.ensureMininal('2.8') runs before wxversion.select('2.8') on
a system that has wxPython 2.8 and 2.9 installed, 2.9 will be selected -
and Pyfa is incompatible with 2.9.

Otherwise, attempting to run Pyfa 1.1.16 on a system with both wxPython 2.8 and 2.9 installed results in a crash:

    Traceback (most recent call last):
    File "pyfa.py", line 88, in <module>
      MainFrame()
    File "/home/tetromino/scm/pyfa/gui/mainFrame.py", line 136, in __init__
      self.statsPane = StatsPane(self)
    File "/home/tetromino/scm/pyfa/gui/statsPane.py", line 71, in __init__
      view.populatePanel(contentPanel, headerPanel)
    File "/home/tetromino/scm/pyfa/gui/builtinStatsViews/resistancesViewFull.py", line 81, in populatePanel
      sizerResistances.AddGrowableCol(i + 1)
    File "/usr/lib64/python2.7/site-packages/wx-2.9.4-gtk2/wx/_core.py", line 15376, in AddGrowableCol
      return _core_.FlexGridSizer_AddGrowableCol(*args, **kwargs)
    wx._core.PyAssertionError: C++ assertion "!m_cols || idx < (size_t)m_cols" failed at /var/tmp/portage/x11-libs/wxGTK-2.9.4.1-r1/work/wxPython-src-2.9.4.0/src/common/sizer.cpp(1956) in AddGrowableCol(): invalid column index