Overhaul packaging & download process

[trptcolin]

There are 2 problems around this:

• The shell/batch scripts in script currently depend on lein1 deps (or at least having dependencies in the lib directory)
• Github downloads is gone, so the "easy-mode" zipfile will need an S3 bucket or something like that set up.

[nelsonjchen]

Second bullet point can be solved with Releases

Example:
https://github.com/git-tfs/git-tfs/releases