Revert "Fixing cygwin path conversion (See https://drupal.org/node/2036001)"

This reverts commit aed5d045d7afc2ef96e258fc9aaecce6eecc50fe.
Wrapper script: make it compatible with cygwin and windows native php
Merge branch '6.x-win' of https://github.com/demonz/drush into demonz-6.x-win
Merge branch 'demonz-6.x-win' into 6.x