Add scripts and lists of required/recommended packages for Cygwin (64bits) and MinGW/-w64/MSYS2
Revert the earlier change which added two possible paths for finding the wxWidgets libraries. These paths are in fact already covered by the _WX_ARCH_ macro being set to an empty string if the build architecture is "32-bits" instead of "64-bits". The alternatives made it possible to find libraries for the wrong "bitness", leading to link problems that are awkward to diagnose.
Add two plausible forms for the installation directories of wxWidgets under Windows/MSVC. The base form was observed in an "official" installation of wxWidgets for MSVC. So to be able to find these libraries I added these two forms (for DLLS and for static libraries).
Minor textual and format changes to the text.
Add convenience batch file for running the exam...