[lmi] wx-2.9.2 warnings

[Greg Chicares]

I've built this tarball:
  ftp://ftp.wxwidgets.org/pub/Daily_HEAD/files/wx-all-2010-11-06.tar.gz
with MinGW gcc-3.4.5, and observe the following warnings. Perhaps some
of them deserve a look if they aren't already fixed in HEAD.

../src/msw/slider.cpp: In member function `virtual wxSize 
wxSlider::DoGetBestSize() const':
../src/msw/slider.cpp:679: warning: converting to `int' from `double'

../src/msw/textctrl.cpp: In member function `virtual void 
wxTextCtrl::AppendText(const wxString&)':
../src/msw/textctrl.cpp:1198: warning: passing NULL used for non-pointer 
converting 4 of `LRESULT SendMessageW(HWND__*, UINT, WPARAM, LPARAM)'

../src/msw/uiaction.cpp: In member function `bool 
wxUIActionSimulator::MouseMove(long int, long int)':
../src/msw/uiaction.cpp:61: warning: converting to `int' from `float'
../src/msw/uiaction.cpp:62: warning: converting to `int' from `float'

../src/common/docview.cpp: In member function `virtual wxDocument* 
wxDocManager::CreateDocument(const wxString&, long int)':
../src/common/docview.cpp:1432: warning: 'docNew' might be used uninitialized 
in this function

../src/msw/mediactrl_am.cpp: In member function `virtual wxLongLong 
wxAMMediaBackend::GetDuration()':
../src/msw/mediactrl_am.cpp:2023: warning: passing `double' for converting 1 of 
`wxLongLongNative::wxLongLongNative(long long int)'

../src/richtext/richtextbuffer.cpp: In member function `virtual bool 
wxRichTextImageBlock::DoMakeImageBlock(const wxImage&, wxBitmapType)':
../src/richtext/richtextbuffer.cpp:7840: warning: converting to non-pointer 
type `bool' from NULL

../src/richtext/richtextctrl.cpp: In member function `virtual bool 
wxRichTextCtrl::WriteImage(const wxRichTextImageBlock&, const wxRichTextAttr&)':
../src/richtext/richtextctrl.cpp:2424: warning: passing NULL used for 
non-pointer converting 4 of `bool wxRichTextBuffer::InsertImageWithUndo(long 
int, const wxRichTextImageBlock&, wxRichTextCtrl*,
int, const wxRichTextAttr&)'