(vim) Improve working with buffers

[tmr08c]

From using Spacemacs, I got in the habit of things like <leader>bp and <leader>bn to move between buffers - this would usually allow me to move back and forth between files.

I added these commands, but Vim's buffer ordering seems to be different than what I am used to.

• Read Vim help doc on buffers
• Read about Vim vs. Emacs buffers
• See if there are plugins that help maintain buffer ordering