ied should create scripts in node_modules/.bin on Windows

Currently ied creates directory junctions for the .bin symlinks on Windows (PR #95) - as junctions work only for directories, this does not work. As discussed in #95, symlinks require additional permissions on Windows, so it's a bad idea to use them.

ied should continue using directory junctions for the package directories, but for the .bin tools, it should follow what npm does on Windows - for each tool it creates 2 scripts:

1. - a wrapper script for Cygwin/MSYS contexts
2. .cmd - a wrapper script for native/any other context