Workaround some bugs in a few boolean returning interop methods

[tannergooding]

This resolves #416

[tdmowrer]

@tannergooding Is this the correct fix? It seems like the real problem is in native code, e.g., here, and this just reverses the logic at the C# callsite.

unsigned clangsharp_Cursor_getIsCopyOrMoveConstructor(CXCursor C) {
    if (isDeclOrTU(C.kind)) {
        const Decl* D = getCursorDecl(C);

        if (const CXXConstructorDecl* CXXCD = dyn_cast<CXXConstructorDecl>(D)) {
            return !CXXCD->isCopyOrMoveConstructor();
        }
    }

    return 0;
}

[tannergooding]

@tdmowrer, its a temporary fix to ensure the managed side is correct.

I'll be fixing the native side, reverting this managed fix, and getting new native packages up with v16.0.0 when that releases in the next month or so (building all native libraries for all supported targets is "very" expensive and takes several days).

[tdmowrer]

Makes sense; thanks!