[lmi] [PATCH] Avoid harmless but annoying arg[cv] shadowing warnings

[Vadim Zeitlin]

 Hello,

 After fixing the 2 "possibly uninitialized variables used" warnings in
a3e46591c01cfc970a715b14b8764002d7eca013, there are just two more (related)
warnings remaining when building lmi with MSVC 2015 and so, even if it's a
minor problem, I couldn't prevent myself from fixing it in this patch:

        https://github.com/vadz/lmi/pull/37

 As you can see there, it just uses wxApp::arg[cv] directly in
Skeleton::ProcessCommandLine() instead of passing them to it from
Skeleton::OnInit() as parameters. AFAICS there is no real problem with
doing it and it seemed preferable to make this change rather than rename
arg[cv] to some non-standard names, which is the only other way I see to
fix the warning.

 It's not a problem for me to keep this change in a local branch, as I need
to use it to build with MSVC anyhow, but it's always better to keep the
differences between it and master to a minimum, so it would be nice if this
could be applied. It could also allow us to enable -Wshadow (currently
commented out in workhorse.make) in the future for the gcc builds.

 Thanks in advance,
VZ