New findwxWidgets module taken from nightly build of CMake. This provides support for wxWidgets 2.9 and 3.0. It also attempts to get the selection of 32 and 64 bit libraries correct by checking CMAKE_CL_64, however, for me this doesn't work. I have added a check for generators ending Win64 which gives correct selection for visual studio, but currently the NMake genrator always gets the 32 bit version. I'm awaiting feedback from CMake devs.