updated download-url; using chocolatey to add %PATH% instead of addpm; t...

Hi,

The package on chocolatey wasn't working so I updated the following:
 - updated the download URL (gnu seem to have left out the "pub" folder)
 - using chocolatey to add emacs bin folder to %PATH% instead of addpm 

Please consider pulling these changes and uploading an updated package to chocolatey
Thanks
Regards,
Lorenzo