Several wxWidgets fixes and improvements
- send wheel data to the PS/2 mouse emulation (wx mouse wheel support works now)
- show selected mouse toggle method in toolbar help and message box
- added capability to start the simulation with the power button


git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12067 6c8e4198-a580-4521-a02f-c9ae86df1db9