Modify the zip file to add client-only option to launcher

[spjspj]

Currently the downloaded .zip contains both the mage-server and mage-client subfolders in it.

Giving a separate download option of just the mage-client subfolder would work to reduce the amount of data needed to be downloaded in the one zip file and still allow people to connect.

Keeping the existing server/client zip file as well would be handy for the %age of people who do use it.

For 1.4.26v1, the mage-client directory by itself zips up to 67MB (7zip on max compression settings)