Reverts to tmux

Readds tmux config (with tmux-powerline).

editorconfig:
  -- Corrects indentation.
	-- Fixes config to work more generally.

vim:
  -- Updates plugin list.
	-- Updates gvimrc with building functions.
	-- Consistency improvements.

zsh:
  -- Updates config for tmux.
	-- Removes TaskWarrior functions.
	-- Sets keybindings to vim-style bindings.
	-- Creates vi function for editing.