Is it possible to build blender scripts in external editor like Atom I have little experience scripting thus far but want to develop my skills further. I am particularly interested in autocomplete features and looking to script geometry within one context for Rhino, Blender, and Processing. Atom handles Rhino and processing, but not sure how to make it work with Blender.

Edit: Is it possible to create an atom package for a bpy/bmesh autocomplete library and send scripts directly to blender? 

Here is how Atom can be used with Rhino Python: 



Scripts can be executed within Atom.
When I was doing this with sublime, I added a "build system" to sublime, essentialy "run this shell code on save", that would run a new headless (or not if directed to) blender instance that ran my script. It was slow but it did allow me to leverage an ide for writing my scripts. It's a bit like setting up a testing framework, and I would recommend additionally setting up a testing framework too so you can know if your script is working and still working without manually, visually inspecting your script results, if possible.