Verify bitness of SquirrelAware apps during install

[caesay]

It's currently possible for x86 squirrel, running on x86 windows, to install an x64 program. Of course, this program will fail to run hooks, fail to create shortcuts, and be entirely useless.

It would be better if Setup.exe verified the bitness of Squirrel Aware apps, and refused to install if the binaries are unsupported on the current operating system.

It would probably make sense to analyse the binaries ahead of time while building releases and storing metadata in the package somewhere, so the executables do not need to be extracted during install if they are incompatible.