Bundle Swarm as a native mac app

[tparker-usgs]

Mac users would like to be able to launch swarm by double-clicking on an icon.

[dlnorgaard]

On Mon, Jun 26, 2017 at 1:30 PM, Shiro, Brian wrote:
8) To make Swarm easier to launch, I suggest bundling an executable for each platform. One of the first things I do with Swarm when I get it is make a Mac-compatible .app file that launches the shell script (and shows a custom icon), which I then put in my Dock.