1. wxShell fixes: now really uses shell (it wasn't different from wxExecute!)

1. wxShell fixes: now really uses shell (it wasn't different from wxExecute!)
   and also added a version which captures the programs output
2. fix for compilers which have void ftime() (my mingw does) in timercmn.cpp
3. updated console sample to test wxShell/wxExecute
4. treetest now can toggle images or change their size
5. wxTreeCtrl doesn't crash if it has no image list

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@6404 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775