[lmi] Latent lmi anomaly unmasked by new wx

[Greg Chicares]

I've upgraded wx{Widgets,PdfDoc}, and all automated GUI tests pass.
The only difference I've noticed so far is that a particular anomaly
is reported: some fields are specified as too narrow in XRC files.
To reproduce, run lmi from the command line, and do:
  File | New | Illustration
Formerly, there was no message on the console. Now I observe:

wxSpinCtrl "SolveBeginYear": initial width 20 is too small, at least 45 pixels 
needed.
wxSpinCtrl "SolveBeginAge": initial width 20 is too small, at least 45 pixels 
needed.
wxSpinCtrl "SolveEndYear": initial width 20 is too small, at least 45 pixels 
needed.
wxSpinCtrl "SolveEndAge": initial width 20 is too small, at least 45 pixels 
needed.
wxSpinCtrl "SolveTargetYear": initial width 20 is too small, at least 45 pixels 
needed.
wxSpinCtrl "SolveTargetAge": initial width 20 is too small, at least 45 pixels 
needed.

at 96 DPI, or at 192 DPI, the same set of messages, but with
  ... initial width 40 is too small, at least 91 pixels needed.
i.e., {40,91} instead of {20,45}.

Running 'winecfg' and changing from msw-7 to msw-xp emulation
seems to have no effect on these messages.

I imagine this means that 20 pixels is too narrow for a spinctrl
(as seems quite plausible), and that formerly wxXRC fixed the
width silently, whereas now it advises us (usefully) of that error.

I'm not going to fix it immediately, because introducing a new
commit now changes the base commit, and we don't want to rebase
for every little thing. I won't forget it because I always run
lmi from the command line, so I'll always see these messages.