added feature to download raw file content

To download from console with tools such as curl, wget we need direct link without javascript.

Utilities such as wget or curl does not support javascript downloads.

I search for solutions and find small hack on http://superuser.com/questions/839083/how-to-show-file-in-browser-instead-of-downloading

I don't know why author of hack is not offered a pull request. 

Owncloud updating frequently and I think that this feature (temporary fix) will not greatly disturb the overall development.

Please merge this with master.

If this need some update to readme(help), please indicate where it should be done and I do this independently and remade pull-request.

Thank you!